I don't eat bread with jam.
I used to eat bread with only peanut butter. That's not a sandwich.
I know Nutella is pretty popular as well. I tried it with bread and don't like it. I like it on its own though.
For me, sandwiches should have things like eggs, meat, vegetables, etc.
Sweets aren't sandwiches. Maybe one day I'll try PB&J and change my mind.