Why do we expect perfection?

Fear of the unknown...maybe the most common fear of all.
I think that around 25 we all get into a crisis and ask ourselves, are we doing everything OK, or am I a mess?
Am I a failure because I'm not what society/my family/my parents expect of me?
Should I be happy?
The last question is really stupid, but is true, we even question in our heads if we deserve to be happy with what we have of if we should look for more and more...
The obviuos question is yes, we ae put into this world to always be happy.
So what's the secret of happiness? I think it is a combination difficult to achieve: self confidence + being possitive + being good to others + living the moment...
Why is it so difficult?
And why during a crisis it seems that the worst in us arises?
Right now I'm facing big changes and although I know I'm smart, nice, and everything I need to make it, I'm afraid to fail.
But it is going to be really difficult to be happy IF I NEED PERFECTION to feel acomplished.
I need to accept that things might not go as planned, but that I'm lucky and very blessed.
Many people like me the way I'm, many others don't...
I think thath everyone has to find their true identity at 20 something, to be happy.
And you need to accept yourself, change what you don't like and just live, just do the things you dreamed of, even if the results are not what you expected.
There's nothing worse thatn indiference to others and to ourselves, to not change is to die. If that's true, risking everything everyday for our dreams is what we need to be happy.