Metagaming is bad.  You shouldn't do it.  Why do people not get that?

Also, uh... Deadpool.  I like Deadpool.  He's a fun character.  But people either RPing as him or as character based on him (and by "based on him" I mean "randomly breaking the fourth wall because [i]zaniness![/i]"), uh... It gets old, unfunny and [i]really[/i] obnoxious faster than you'd think.  It's far harder to actually write him well than people tend to realize, and I think I've only seen him written well in an RP [i]once[/i].  I've actually seen crossovers that put a blanket ban on Deadpool because of it.  But hey...