If you try to remember and think back to your earliest memories...there are events captured in those that have shaped who you are as a person today. I gaurantee there are memories you've held onto in your brain this whole time you've been alive because they stood out to you, and you learned a lesson. 

For me, I have a memory of getting in trouble more than once for eating only the marshmellows in the lucky charms cereal. After stubbornly refusing to comply, and when forced to obey, I did so relunctantly with bitterness and anger. I would only get acceptance unless I performed to a certain expectation. She was right. I have to eat the other cereal parts. To this day that cereal reminds me.

Wow who knew lucky charms cereal was a memory of stubborn crossfires between mother and 3 year old daughter?

That is a trigger. When someone tells me I can't do something.