This is only one reason, but one way in which SJs suck is in how terrible they are at acknowledging their shortcomings...or at least letting other people discuss their shortcomings.
Cue next SJ post: "Nuh uh! I'm always open to criticism! I know all of my flaws...like being too responsible and caring too much about other people and working too hard."
I'm sorry to say it, but you're right. (I do NOT care too much about other people... when people get emotional, I want to hide in a corner. Same with myself, actually.)
But Bella and Cimarron are right, too. I admit it when I'm wrong if I didn't put a whole lot of time and effort and commitment into whatever I was arguing. If it's a petty thing, than I'll be happy to side with the correct argument instead of my own. HOWEVER, if I get really into an argument and then realize I'm completely off base, my reaction is such severe embarrassment that I don't want to even talk about that topic anymore. (Hence the "not letting other people discuss their shortcomings".)
Slightly related anecdote (with the fault being something entirely different):
EJCC: *trips and falls in large crowd, skins knee*
Crowd: *gathers round* OMG, are you OK?
EJCC: *embarrassed, mad* YES! Go away! Leave me alone!!
When a normal person would have responded:
Normal person: Yeah, I'm OK. Just tripped over a crack in the sidewalk. Dumb, huh?