Is lettuce really necessary in a salad?

Who the hell mandated that lettuce must be in a salad. I feel guilty if I don't have lettuce in it. Lettuce really doesn't bring much to the table (pun intended) and many times can be overbearing and spotlight hogging. Nobody wants lettuce to do that. It's kinda like that fat annoying guy you know that you don't want to invite to a party but you feel sorry for him, so you do it. Fuck you, lettuce!