Since then I've looked at the ingredient list of every other product with great suspicion, expecting to find mayo everwhere...
I use butter and mayo for one of two things: flavour (eg I love kerry gold on toast ;-) often nothing else) or moisture - but if I don't need the moisture, usually because I've got tomato, peppers, coleslaw, relish or something else providing that, I will leave butter and mayo out. Unless I want them for the flavour. (As an side, I don't understand why people would ever want butter on a breakfast roll)
These are precisely the instances in which I would want something oily (butter, marg or mayo) as waterproofing for the bread. (Mustard also works, if it's appropriate for the sandwich.) "Everyone has the gout," as they (don't actually) say in French.
I just don't need a peanut butter and butter and jelly sandwich.
I thought garlic fries, like the sort at Giants games, were delicious! Some garlic, olive oil, parmesan, etc. I was shocked to discover that here and in the UK garlic chips consist of chips (fries) with garlic-accented mayonnaise spread all over them.
And don't call it Aoli. That's just dressing up a disgusting condiment with a fancy word.