I don't know that crepes are the right venue for peanut butter, especially if it's natural peanut butter, which is gritty and not sweet. While it's true that store-bought peanut butter in the US has too much added sugar, that really shouldn't matter. Ground up peanuts are filling, energy-dense and delicious. Why do non-Americans dislike it so much?

Why do Americans torture themselves like this?

The finest crêpe I ever ate was peanut butter, banana, and honey from a street vendor in Baden-Wurttemberg at 2am. There may have been ethanol on board, but I stand by the claim.

Man, I love peanut butter. I could eat it out of the jar with a spoon. Sadly, I'm now allergic to peanuts.

It never tasted bitter to me. But I always got the brands with sugar and salt mixed into them.

Yeah, that sounds like it would be a textural nightmare with how thick and heavy peanut butter is.

It's very rare to eat peanut butter on its own. It's most famous for the way it pairs with other flavors. Peanut butter and jelly (strawberry jam is a classic), peanut butter and honey, peanut butter and chocolate, or if you want something super extreme peanut butter and marshmallow fluff.

I would bet you'd like it more if it hadn't been peanut butter only.

It sounds like you ate bad peanut butter. It should absolutely never taste bitter for any reason.