The truth is we all have our own +'s and -'s. Saying "I am the best" doesnt' make it so. It just makes people arrogant and mean. I think everyone is intelligent in a different way. A comedian may have a different intelligence than a scientist but that doesn't mean that they are dumber. Beauty doesn't add to the "best-ism" either.
So, people who go out their telling themselves they are the best are just making fools out of themselves; nothing more. It's okay be confident but to be over-confident is silly!