Why do people care about apperance so much?

This bothers me for a long time now. People who laugh at other people for the way they look. Skin colour, hair colour, thin lips, way too big lips, no boobs, no ass, crossed eyed, no abbs. I could go on for hours. Point is, we get stupid comment about the way we look. Even though we didn't choose to look this way.
There is a differance between taking care of your body and being born with certain features. Why can't we just accept each other and life our lifes?
'I want a man with a sixpack and blue eyes' 'I want a girl with big boobs nice lips' please get realistic. In the end when we grow old we will have saggy boobs and lose skin. Wrinkles and no or thin hair. It just disgust me how people hurt eachother just because they don't like what they see. I wish everyone looked the same. Then we could just find that person that we truly want to be with.