[quote=@Inkarnate]
How about people who claim to be open and inviting to new members but want to play the main characters thus regulating the playerbase as supporting cast? I've run into this a few times and I hate it.
[/quote]
 
This +1

I tend to play more supportive characters generally, but that doesn't mean I want to be stepped on and treated like I'm less important because I'm not in your damn little circle of friends. 

This is one reason I don't join RP's that are far in already even if they are open; People tend to stick to who they already have, and make gaining more interest generally pointless. Though this isn't everyone, obviously.