Expectations
In life one must learn to expect and depend on nobody but themselves. Unfortunately, human beings as I like to believe, we are designed to either fuck up or please people and I can guarantee everyone/anyone reading this, they've experience both.
Strangely though, fuck ups hurt like a motherf*cker. It makes every time you was pleased by someone seem so nonexistent.
Strangely again though as humans no matter how many time we vow to never let our guards down and not get disappointed again, we find that one person who does just that.
I don't know, these are just my thoughts.