How to Deal With a Know It All
Know-it-alls can be incredibly annoying, but you can handle them by avoiding confrontation and trying to engage them in conversation. Try to keep your topics of conversation light-hearted, which will make it easier for you to brush aside their behavior. Don't feel like you need to respond to everything they say, since the best response is sometimes to ignore them. Alternatively, acknowledge them in a non-committal way by saying something like, “Thanks for your suggestion” or “That's an interesting point.” If you want to engage the know-it-all, make sure you have facts to back up your points. These could be things like statistics, quotes, or reports.
Try to be understanding. Most know-it-alls have a reason for acting this way. Whether it is a personality disorder, the need for excessive admiration, or arrogance, know-it-alls have issues that have to be addressed. Trying to understand where they are coming from could go a long way in empathizing with their condition.  Try to tolerate a know-it-alls behavior and avoid the impulsive fight-or-flight response by understanding that differences between people will always exist. The root to all understanding is respect. It is unreasonable to think that anybody would suddenly conform to your ideas, which took you a lifetime to develop no matter how strong your perspective. If you want a know-it-all to respect your opinions, you will have to respect theirs as well. Only when you can appreciate a know-it-all for who they are can you finally realize and understand where they are coming from. Think first before responding. Since know-it-alls are annoying it is easy to respond in anger or worse. Therefore, take time to calm down and diffuse your anger before thinking of an appropriate response. Typically, taking time to think about the situation might even increase your confidence in dealing with somebody who “knows it all.”  By thinking first, you can formulate a better response. Most people think of responding while the person in conversation is still speaking and you do not listen to everything being said. When responding to a know-it-all, it is best to have a clear, thoughtful, and pertinent reply that is more likely to be accepted by them. Stopping to think prevents saying stupid things that destroy friendships, start fights, or create awkward situations. It also does nothing to solve your issues with the know-it-all. A thoughtful response also receives more respect. It is tough enough for a know-it-all to accept a response that is not their own, but a thoughtful and considerate response will more likely be accepted. Lead by example. Do not be afraid to say “I don't know” around a know-it-all because this demonstrates that it is okay not to always know the answer. Being a model of appropriate behavior might open the door for others to feel confident in not knowing, including know-it-alls. Follow up statements by asking questions and getting diverse ideas to illustrate flexibility and inclusion.  Saying “I don't know,” can also build trust by demonstrating openness, vulnerability and honesty. Other ways to say “I don't know”: “I don't know the answer to that, but I'm anxious to find out”; “Let me tell you what I know, and what I'm still learning”; and “I can't tell you that with certainty. I do have an informed opinion on it which is…” Offer constructive feedback. Believe it or not, know-it-alls might be ignorant to the fact that their behavior is negatively impacting others. If you detect this, take them out for a coffee or set up an appointment in private to discuss it gently and respectfully.  Although know-it-alls often exude confidence, they are oftentimes suffering from insecurity. You will have to stroke their ego or compliment their range of knowledge before informing them of their negative impact. Soften the blow by telling them that it is important that everybody gets a chance to add their input because it provides a sense of community. Agree on a resolution. Any solution dealing with a know-it-all should evolve from a trusting relationship for it to work. Try to speak assertively and respectfully while working out a solution until the behavior changes. If the respect is mutual, the know-it-all will try to work out a resolution with you. Consider the know-it-all's perspective by not relating everything they do to evilness, stubbornness, or unkindness. Remember that you do not always have to accept their opinions, simply just acknowledge them. Keep an open mind and good attitude to help solve any issues. Be patient and listen to what is being communicated. If you are not sure, ask for clarity or explanation. Flatter their wide range of knowledge. If you want a know-it-all to listen to you, you must appeal to their sense of self-importance. Since they are not naturally good listeners, you will have to create some problem that you want their advice on. This gets their attention since you appealed to the value of their opinion.  Ask something like, “I have a problem waking up in the morning, what do you think is the best way to get started in the morning?” Arm yourself with facts. Prepare verified facts when entering into a conversation with a know-it-all will limit their negative impact and opportunities to interject.  If you are giving a presentation, hand out an agenda ahead of the meeting with a time limit for each phase of the talk. Add statistics and cited facts that are indisputable. Preparation is always the key. The more prepared you are to defend your perspective the better off you will be in dealing with a know-it-all. Counter their know-it-all responses with truisms. If you prefer to be a little more direct you can preempt statements with truisms that give little room for a know-it-all to get involved in the conversation. Since truisms are obviously true, know-it-alls can only offer moderate, less overbearing responses. Before making a statement, say “If we are open to all possibilities, then we could look at it this way.” These types of truisms throw off know-it-alls because it is directed towards them making them have to rethink what they were going to say. Or, after a know-it-all provides their response, say, “I am shocked to hear this because I thought your perspective would be different.” This surprises them because you are questioning their response without being too confrontational. Use reverse psychology. A know-it-all is often a contrarian – you say “day,” they say “night.” They just cannot help themselves. Being a contrarian compels them to say the opposite even if the truth is overlooked just to hear their own voice. Coerce the know-it-all to have to agree with your position by presenting the opposite perspective before making your statement: “I know you will disagree with this; indeed, you will certainly think this to be ridiculous, but…” Now the contrarian has no choice but to agree with you. Become a broken record. Sometimes the only way you can get a know-it-all to accept your position is to repeat it over and over. You must be resilient and avoid getting caught up in their perspective. The strategy is to make them figure it out on their own through dogged repetition and to exhaust them to the point of surrender.  For example: “I understand how important it is to you, but I don't want to do it…seriously, I don't want to do it…Yes, of course I am very clear how important it is, but I don't want to do it.” Or, “I think it is too expensive…Sure, it's a good deal, but it's too expensive…I understand there is financing available, but it's too expensive.” Ask probing questions. Know-it-alls enjoy being contrarians and voicing their perspectives. If this becomes too annoying challenge their responses by asking detailed questions to break down their position. This forces the know-it-all to be better prepared before blurting out answers they cannot support with evidence.  Be respectful, but ask specific questions about their sources, facts, or experiences. Do not be afraid to confront a know-it-all about their expertise or authority. Do not take it personally. Since know-it-alls are essentially correcting all misinformation by providing the “right” answer, they are, by implication, putting you in your place. This is a serious challenge to your authority and self-esteem. Know-it-alls, however, cannot help themselves because they think they are doing you a favor by informing or correcting you.  In these circumstances, try not taking it personally by taking a few deep breaths or taking time to think about your response before blurting out some offensive statement that will only embarrass yourself. Remember, know-it-alls do not perceive most people as stupid or uneducated; rather, they have just not learned the difference between presenting a fact compared to an opinion. So, keep calm and collected and just let their replies roll of your back. Choose your battles. Not every response by a know-it-all needs to be addressed. Doing so will only exhaust and stress you out.  Try to keep moving forward by either ignoring them or simply say, “thanks for the suggestion,” instead of getting involved in a fruitless conversation that you did not care about to begin with. Ask yourself, “is the situation so distressing that it needs to be addressed?" This is an important question if you become emotional. By asking this question, you can bring yourself back to reality and decide whether a response is healthy or harmful. Keep your sense of humor. To avoid a confrontational encounter with a know-it-all, keep your conversations non-aggressive. Smile, take a deep breath, and avoid using sarcasm no matter how tempting. Keeping the conversation light and humorous allows you to shake it off without further worry.  If you feel yourself unable to smile or laugh it off, take a step back. By taking a moment to disengage, it will be easier to recognize how silly it was to get mad in the first place. Try to reframe the situation in a way that you are viewing your response as a spectator. In a frustrating situation, try to recognize the potential humor in just how ridiculously annoying it is. In this case, take the situation to an extreme that is impossibly ridiculous to the point that it makes you laugh. Even a fake smile helps release endorphins, making you feel better and happier. By placing yourself in a happier place makes it easier to keep your sense of humor in trying times. Try avoiding them. If all else fails, do not invite them out, do not frequent their favorite places, and do not return their phone calls or emails. Although this is cruel on many levels, maintaining your sanity and health is more important. If you work with a know-it-all it might be hard to avoid them. You might have to pretend not to hear them, smile politely and not respond to them, or leave the area when you know they are approaching. Change the topic of conversation to something they are not interested in or cut them short when they try to reply. This lets them know that you are not interested. 
Try to be understanding. Think first before responding. Lead by example. Offer constructive feedback. Agree on a resolution. Flatter their wide range of knowledge. Arm yourself with facts. Counter their know-it-all responses with truisms. Use reverse psychology. Become a broken record. Ask probing questions. Do not take it personally. Choose your battles. Keep your sense of humor. Try avoiding them. 