I love RPing (but haven't really done LARPing), and it has actually inspired me to write some fiction for the first time in decades. I tend to get annoyed, though, when playing with people who can't answer (what seem to me to be) really basic questions about their characters. Sexual orientation? Relationships with friends/family? Hobbies? Favorite food? I character I "get" will "tell" me the answer to all those and more. Characters whose players don't even think about such things seem terribly flat.