You think you're not pretty. There's always someone uglier. You want more money. People are in poverty. You want a boyfriend. Someone doesn't even have parents. You're hungry. A child is starving. You want to go to the mall. Someone is looking for anything they can just to stay warm. You're chilly. Others are frozen. You just want to die. Most people want to live.
So don't waste your time on things that you want because there is always someone out there who needs it much more than you could ever possibly know.