Well, I read the one about the breast size problem and I want to give a man's perspective:
When you don't think you measure up, you do not have enough confidence with Women. (and men, if you are that way) I never got married, and dated a few times, and had one successful sexual experience, but there was this time I had 3 chances to perform, but I couldn't. then I was "out".
I think it was because I felt like tiny tim. How can one ever have a good self esteem, especially if people know your size, or you have to strip naked in a situation, like a shower room, or to have sex with a woman?
What about being ridiculed in school because we were made to strip and shower for P.E.???
And every girl that knows me, or I think knows me is probably thinking "he's got a little one, I don't want him"
I can have good self esteem, until anything about my privates in involved, then I feel like crawling under a rock.