The difference for me between no foreplay and foreplay is like the difference between grape Kool-Aid and wine (in a manner of speaking)
Seriously though, I definitely have an easier time getting "out of my head" with foreplay. And not just a couple of minutes of it, but a legit session of tease-me-please-me-and -don't-be-in-a-rush activity.
very important. Without foreplay I am not going to have an erection, and my girlfriend is not going to be lubricated or relaxed. Understandably this is not the case for everyone, but for me no foreplay basically means no sex.