Because my capacity to deal with them like a healthy human is nonexistant. 
It's raining outside and I didn't bring a coat? 
Time to get really, really angry and swear loudly regardless of the fact that people are witnessing me act like a lunatic. 
Wake up late so I can't get coffee? 
Time to fight the urge to throw something or punch something. 
I am an adult toddler when it comes to dealing with anything that even remotely inconveniences me.
  I can literally feel the tension in my body build up over this shit and I will stew and stew until I snap at somebody because I need to release the tension. It's terrible and not only does it contribute to fights with my S/O, it's also incredibly unpleasant to just feel this angry about small things. I'm pretty sure I'm going to have an early death because of how tense and stressed I get. 
Am I the only one? 