Oil
I can appreciate brushing some oil round a frying pan; and although I have long since had to give up deep or shallow fried potatoes at home, or fried bread, I occasionally need to brown some raw beef, mince or the occasional hamburger patty (the things dubbed in defiance of etymology "beefburgers").
I have some American recipe books for muffins and brownies, and in some recipes oil is used instead of margarine as the fat content. I'm happy with that too, because the result is cake. (Even eggs are acceptable in a cake recipe, though nowhere else.)
What I cannot understand is when people will quite deliberately, and of their own free will, take perfectly innocent lettuce (picked, washed, and ready to eat) and pour oil onto it as though this will somehow make the eating of it better, rather than rendering it utterly disgusting.
Of course, they don't always (or even usually) stop there; they mix up these horrible concoctions with not only the slime of cold olive oil but the filthy taste of vinegar, and the sickly sulphur of raw egg, and they dump dollops of the resulting non-drip emulsion paint on everything in sight. As far as one can tell, some people never eat anything savoury (meat or fish based as opposed to sweet like dessert) without this almost unspeakably disgusting glop all over it.