Don’t get me wrong, if you have a good jam or preserves it’s totally fine on a sandwich, and I wouldn’t turn my nose up at it. However, peanut butter doesn’t really need the help, and the extra sweetness from jelly is totally unnecessary. Toasted bread and peanut butter is all you need for a quality simple sandwich.
Are you talking about just-peanuts peanut butter, or the sugary Kraft style peanut butter?
Just peanuts, I find the sugary peanut butter to be kinda inedible.