Probably because they feel embarassed when people see them playing a game with a retarded looking smile on their faces and giggling (Got myself caught doing this, forgot the mic was on) due to the enjoyment of having friends and strangers playing together with them.
I know this is not really the case, but anyone find themselves constantly smiling as they smack their buddies around? Or laughing because a PSN buddy *cough* Blazinhead89 *cough* can't make a simple jump and plummet to their death?
Ahh... nothing like smacking someone as they are about to complete a long jump over a pit of fire. "Get in that fire!" 
iPhone = Great gaming device. Don't agree? Who cares, because you're wrong.
Currently playing:
Final Fantasy VI (iOS), Final Fantasy: Record Keeper (iOS) & Dragon Quest V (iOS)
