John Mayer is definately an ENFP. I've come as the sensitive type often, and had social phobias. Its not far fetch. Overall, his general behavior, lifestyle, messages (not execution) and eclectic interest designate him as a typical ENFP.
The guy reminds me of a real life Vince from Entourage. The thing that gets me is that folks like John Mayer, Vince, and such are also coined as full of themselves - and overall douche bags. Why? There is an air of confidence that comes from them that is truly annoying, intimidating, and basically calls for someone to put the person in their place. Basically, I feel these specific guys, such as Tom Brady (ENTP??) give off this air of confidence and its very easy for someone to look at them and say they are cocky. Personally, I think it's confidence. It isn't like they don't often discredit themselves, or anything of that sort. However, that isn't the point. The point is that often these guys that most people want to say are shit or talentless, and are hated, mostly for their confidence, accomplishments, or perceived cockiness, often win people over in real-life interaction because when you involve yourself with them it's clear it's not bullshit. They are being geniuine...or as geniune as they can be.
Such as this...
[youtube="http://www.youtube.com/watch?v=wztDFRpWkR0"]Tom Brady[/youtube]
The thing is, I'd at least hope that us ENFP can win folks over that hate us, sincerely, like so. I hate to be hated. It hurts. Bad. Either way, I'm sure this guy is an eNFP.
[youtube="http://www.youtube.com/watch?v=f9-AF3lt2l8"]John Mayer[/youtube]