Unperfect

 "Tell me what's perfect?"
When I say "mug is empty" you know what I mean. When I say "mug is full" you know what I mean. If there might be situation where some one doesn't know what empty means, that person can't know what's full 'cause that person has nothing to compared.

So with out empty, there can't be full. So with out unperfect there can't be perfect.

I thing that perfect needs to have little bit of unperfect to even be exists.