If you really want to eff up your kid, tell them all the time, "why can't you be more like (insert supposed superior human being here).
My poor nephew, Tommy, has heard this all his life - why can't you be more like your older brother, Wes?
It destroyed him. He's 25, has abused all kinds of drugs, spent several years in jail - his mother died while he was locked up - and finally tried to kill himself by jumping out of a moving car. He is now in a coma with only a feeding tube keeping him alive.
Children should be allowed to be themselves.