I met John Mayer at K'rd Rockshop on his first NZ tour. He came into the store and I sold him a couple of things. It was not long after that first album hit big......when everyone knew him as a teeny-bopper pop boy and had not yet figured out how great a guitar player he is.
I can confirm that even back then, he was kinda unpleasant to deal with and came off to me like a gigantic douchebag (and I do mean gigantic - he's quite a big guy). I won't regale you with the full story, but he left me with the impression that he looked down his nose at us mere retail mortals and was anxious to display how rich and successful he was.
I'm sure he's probably mellowed out a bit as he's "past participle of get" older, but I still saw shades of that arrogant dude I met on those Where the Light Is interviews.
But yeah.....having said all of that, I really like his guitar playing and tone. The guy knows what he's doing!