That is true, but equally it's easy at times to hide behind others in a session setting. I've heard myself in session recordings sounding like I'm blending nicely (even though I wasn't trying to hide), yet when I play the same tune to myself at home I can hear all the flaws. Crap intonation, poor internal rhythm, no drive, dodgy or inconsistent ornamentation, a bit of ego creepin' in... Having said all that, mind you, you do need to be able to hear the flaws. Can be a useful exercise but not worth dwelling on for too long. There are times when I can't hear myself too well in a session. A gob iron too close to strummers, etc...