Being British, I grew up with Sun-Pat peanut butter so I don't mind it at all, but it's certainly different, and if you're not familiar with its texture and taste I suspect one of the things which would be immediately noticeable is how it tends to be "clammy" and stick to your mouth more at first. So I'm certainly not averse to enjoying some tasty Skippy peanut butter.
Peanut butter & jelly? I think many Brits have only ever heard of the combination by way of TV or movies, and sometimes don't realize at first that jelly is jam. Even so, I'd say a lot of people still find it an odd combination, and it's not something that a lot of British children grow up enjoying, but here I am at 42 years old and I love the combination!
I've never even thought to try jelly/jam on steak before, but I do love maple syrup on bacon, which is something else than many Brits seem to consider extremely odd.
Reese's peanut butter cups? Funnily enough, I tried them for the first time yesterday (at least as far as I can remember I'd never had them in the U.S. before). Delicious!