Is there Best OS..

I used, windows, linux, BeOS, Macosx. But I can't think about witch is good???? Is there best OS? Problem is, they have good areas and weak areas differently. So, I can't get all with one OS. But, I can't use two OS's, because it is painful. But what to do.. I definitely think apple, windows, linux are great. But, I don't feel like they are best. why can't they think as pack and get build best OS? clearly I want to live that kind of world.