If you have ever had a hotdog or a burger with ketchup you have eaten just bread and ketchup at some point. Theres always a corner that doesnt have any meat in you just nibble out the way :P
I don't eat bread and ketchup on their own willingly though, nor bread and mayo. If i really cba to make a sandwich, i just get a slice of bread, throw some marmalade on it and fold it in half. Instant sandwich. Mayo and scotch eggs is a good combination.
I've moved more onto brown sauce with my sarnies now days though...