I have a toddler who is 3 years old.  Let me tell you - Parenting is a difficult and confusing process to help develop the child from infancy to being an adult.
I am childless, is it really that difficult?  By three they should be self sufficient shouldn't they?
That's what I thought too - until my kid started being very attached to me.  Then I learnt about many different type of parenting skills and coping mechanisms, such as attachment theory.  
Attachment theory, what's that?
It's the theory that describes the long term and short term relationships between people.  For example, my toddler wants to consistently be around me when they are scared to receive emotional support.  The issue is, she gets scared of anything that is new to her.
Does that then encourage her to be afraid of things since she knows you are going to be right there?
I believe the triggering events are when she's separated from her loved ones or seeing a potential threat (such as darkness when sleeping or when I have to take a shower and leave her alone).  I don't believe it encourages her to be afraid but rather seek comfort in challenging times.