Chocolate spread is brand new. I've never had it. Sounds nasty honestly. PJB is a favorite but I do not eat it much. I guess that is why I enjoy it so much when I DO have it. Nutella is an Italian thing that is gaining popularity in the US. Personally, as good as it sounds, I will not be making a sandwich out of it.
Your ruisleipä looks good. I think a schmear of peanut butter would go nicely on it. :) Salted fish on the other hand I can do without.

Not all three at once. Usually it's just grape jelly and peanut butter. The Nutella spread is a separate sandwich. The PB&J is a classic school lunch. Nutella is a funny thing. It's always been right there on the grocery shelf, but it recentlly took off as a new fad.

White bread and many grain breads like whole wheat and oat actually have a somewhat bland or sweet flavor. Toasted wheat or oatmeal bread is quite delicious with honey, chocolate spread or jam. Americans also eat dark savory flavored breads like rye and pumpernickel, and we put meat and cheese on those, though I personally like peanut butter on mild light rye bread.

Not all at once, but yes.

Bread, or at least most bread sold in this country, is sort of a bland blank slate, which you can put either sweet or savory things on to good effect.

I wouldn't say most of us eat bread like that *every* day. But it certainly wouldn't be *unusual* for someone to have, for example, toast with jam or jelly for breakfast most days, or (especially if a kid and/or kind of poor) a peanut butter and jelly sandwich for lunch.

Nutella is from Europe. I've had it in France, on croissants. They're trying to sell it here as something to eat for breakfast. I don't know how that's working. Peanut butter and jelly is a common sandwich for kids for lunch. It's very good- and peanut butter is good on rye bread, too.