I actually find twitter names to be fairly annoying. I've never actually voiced that opinion though since the facebook sharing model seems useful and the twitter sharing model always seemed useless to me (the only actual use I have ever been aware of is that some publishers use it as a worse RSS feed). The <140 character messages from people I don't really know are a sizable portion of Facebook, and are always by far the worst part of it.

Pseudonym vs actual name is correlated to that spectrum but not a direct relationship. People's stupid names is definitely something that makes interactions on reddit, AIM, video games, twitter, etc feel really immature to me compared to Facebook.