For me, it can all be boiled down to one simple sentence: "I'm not good enough".
I'm not good-looking and feel ugly most of the time.
I'm overweight and have never bothered trying to do anything about it, no matter how many times I tell myself I'm gonna exercise and start eating better.
I have no talent whatsoever; can't sing, dance, act, paint, play any sport. I was told I had a good way with words but any time I try creative writing I give up after a few minutes 'cause I tell myself that what I wrote was rubbish.
I'm not smart enough, at least not anymore; I flew through primary and secondary school but fúcked up college a bit.
I'm obsessive to a degree where things I did when I was about 6 years old come back to haunt me. I can never let go of the past and keep getting depressed over things that happened ages age, even though I know I can't go back and change them. I'm like a broken record, complaining all the time. I have bucketloads of regret about even the silliest, most trivial things.
I'm really open and honest with strangers but when I get to know someone I close up and can't be honest with them. I act like a different person around my family than I do when I'm with my friends. So I'm not even good enough at being me!