I usually trust my own ears, but I've had times, usually when general fatigue has a grip on me, where my ability to hear pitch starts to go! Just last night, during the fourth gig in three days, my bass sounded significantly sharp to me, even though the tuner said I was right on. Well, tuners can lie, so I asked my bandmates and they both said I was just fine, and no one in the audience had that "there's something wrong" look on their faces, either.
I had that problem all through the first set, and then, after a break, my hearing returned to normal, and it all sounded good again...
Weird!
Tim