I've always ran into rude people. While what you guys have said above is pretty bad, I think everyone that types 'casually' when OOC (for example, 'lol what are you doing', 'omg craig no') has come across the lot that harass you, call you names, and what-not because you type this way. They're not nearly as bad as what the people above had said, but they're damn well common. While I usually shrug off whatever they say and titled them arses, they make it clear they think you're the lower scum of the earth.
"You're juvenile", "If it's 'easy to type our way, why not do it all the time?", "God, bunch of three year olds", and "Come back when you learn proper English" have always been a few common things that have been said under these circumstances. Just cause' we decided not to constantly capitalise or use punctuation.