SOOOOOO important!
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.