Personally, I feel it's hard for us people without a small penis to give any real advice on this issue, at least those who started at at least an average size. Why I do agree and can attest to myself, even though a guy may be average, he might have more problems with it than a smaller guy who has accepted his size. However, all things being equal, I don't think we can honestly give naturally small guys much shit about "how it doesn't matter."
First of all, us members who were born with average or bigger penises aren't going to encounter the same type of pressure as small guys do. There is a lot of bad press out there, etc, that does cause worry to those who are "lacking" (according to society) in the penis size department. It creates a whipping boy image in which people can easily get into and make fun of without feeling bad by hurting their feelings, kind of like laughing at someone because they are black, people with mental handicaps, old people (although much more tolerated). However, while society has a sort of "filter" in for the racist and other prejudiced feelings, it does not have a "filter" for people with small penises. They can be openly ridiculed and everyone can participate without feeling any remorse. I've seen guys in the high school locker room made to feel like shit because they had a small flaccid penis. I never participated in any of it, but I couldn't image what pain and HELL those people being picked on were going through everyday, every time they saw themselves in the mirror, or every time they looked down. Another good example of a societal "filter" is with fat women vs small-penis'd men, you most likely won't ever straight-up in public (group setting that is sober) call a girl fat in front of her face and laugh, whereas I have seen this happen openly with guys, mostly with the guy not actually there to hear it though.
I admit that I'd handle my life somewhat differently if I were born with a small penis. By how much? I have not a clue. But it'd definitely be something I was MUCH more concerned about if I did have a small penis. When it came to sex I probably would be a great deal more scared about what she though, whereas now I could literally say with absolute confidence, if a girl ever complained, that "your pussy is broken if you didn't come from this dick." Of course I wouldn't be that pompous to believe that just ramming my dick in there will make her come, but I would brush it off my shoulder like it wasn't ever even there. A man with a small penis can't do this unless he REALLY has some frame control.
The best advice I could give to anyone out there who is small, if you're not TRULY happy with it, give newbie Penis Enlargement a shot and build from there, while working on your mental issues through several methods: meditation, some sort of counseling (a Penis Enlargement board is great, like this thread), or getting new hobbies (it makes you a more interesting, well rounded person).
The small members here get some immediate respect from me, because I won't ever have to potentially go through what they may potentially be going through.