Back home, where bananas are plentiful and come in various varieties and sizes, we use them only for desserts like deep-fried banana, banana pudding, banana cake, banana split ice-cream etc. So banana with mayonnaise therefore needs some time to get used to.
The proof of the pudding is in the eating!
Light years ago, my mom would slice a banana, place it on a leaf of lettuce and spread mayonnaise and sprinke cocktail peanuts on it. Just wondering if anyone ever heard of it. It is quite good, actually.