Something I see quite often on the Internet and occasionally in real life: the people who are the biggest beggars (in terms of sexual partners) are also the worst choosers. Men who never get laid pontificate about how every gorgeous actress and model just isn't thin and busty enough for them to be attracted; women who are chronically single lay out ridiculous "he should be a PhD. and have a six-pack and also blue eyes" requirements for men they'd want to date.
Not that people don't have the right to be choosers. Don't settle for someone who won't make you happy because you think they're the best you can get. And if you're committed to waiting until Dr. Blue Eyes PhD. comes along, have fun with that. But it often seems like there's something more going on here.
It's partly sour grapes, of course, but it's also preemptive sour grapes. If you are afraid to approach men or women, saying "I like girls, but the ones around here just aren't good enough" allows you to pretend you're not a wuss while justifying your behavior. I've seen it used to justify PUA nonsense too--PUA works great for me, but I only use it on 10s. Other times it's part of the same ego-overcompensation complex that drives pudgy nerds to claim they're masters in martial arts--only the best women are good enough for an 18th-dan ninjitsu black belt!
It's always amusing to see a group of Internet dorks declaring that Alyson Hannigan is really showing her age these days and they'd never lower themselves like that, but it's also sad. There's little difference between raising your sexual standards sky-high and giving up on sex entirely.
(Another weird, possibly related PUA phenomenon that I've seen: the inability to acknowledge the existence of average women. I was reading a thread on their goofy 1-10 rating system and every photo they posted was either seriously physically flawed or Photoshopped-model gorgeous. There were no 5s. Shit, if I thought models or trolls were the only choices I'd hold out for models too.)