'Be yourself'
What if myself is stupid, arrogant, skinny etc surely it's better I become intelligent, humble and musclely. Surely I would be much happier if I followed this advice instead.
And what the hell is a self, I subscribe to the bundle theory and the Sartre notion of 'existence preceeding essence' I can define myself however I want and in terms of natural selection, it's better I be intelligent, humble and have muscle.
Guess what, people that be themselves get owned by natural selection because they fail to adapt.