Because you can't give yourself the love and affection you really need.
Loving yourself is like having sex with yourself: What’s the point? It is a shameful, dirty practice to be avoided at all cost. If everyone went around just having sex with themselves, how would we keep the human race going? And if everyone went around approving of themselves, how would we keep the rat race going? Consider this: if you loved yourself and approved of yourself, what would you need other people for? Do you want to be considered arrogant? Do you want people to envy you? Do you want to make other people resent you because you seem self-satisfied? No, of course not--because then how could you get the love and approval you so desperately need from them?
I didn’t think so. So wipe those smug thoughts out of your mind and get down to the serious business of looking good. .