The only thing i could say after 15 minutes of awkward back seat sex was, "if we don't date, will this suck?" and that snowballed into such statements as, "i don't really know if i want to date you just yet" and "i feel as if the physical aspects of our relationship are carrying all the weight that the emotional aspects should."
Anyways, she is now extremely pissed and, as a guy, i have not an exact clue why. This isnt the first time we've said things like that and it isnt the first time we've said it after being physical.