Let you down?
I don't understand why artists change the lyrics to songs like that.
I find it really annoying! Especially when it changes the intention entirely! Once I heard a cover of John Lennon's "Happy Xmas", in which the "let's hope" of the "let's hope it's a good one" line was changed to "let's pray" - something which I'm sure Lennon wouldn't have been very impressed with ("Imagine" summed up his thoughts on religion pretty well). So JM's keep/let change alone put me off listening to any more of it...
That said, I quite like John Mayer, although I haven't listened to any of his material for quite some time now...