Well, as far as 'patronizing jammers' goes--
I attended a dulcimer festival here in MI, and was playing the piano in a big jam--my first time "out in public," instead of just playing with the folks I knew from my local folk group. All was going extremely well, and I was quite pleased.

Next thing you know, "Patsy Patronizer," (name changed because I'm such a nice person), a woman I knew from the group back home, comes and joins in the jam, after we'd been playing for an hour or so...

She sits down at her dulcimer, and begins *hollering out chords* in my general direction, as if I didn't know what to play. (She'd done it before, so--YES, I knew she was doing it to me. She'd been playing quite a while before I ever started, and had to remind everyone of that fact quite often.) I was quite irritated, as were some others, but gritted my teeth and finished the tune. (If you've ever had anyone holler chords, you'll know how annoying it can be--by the time they've played the notes, processed them in their brain, sent the message to their mouth, hollered out the chord name, and then YOU hear it and process it, there's at least a 3-bar lag!! There are few things that annoy me more...)

After we finished that tune, I turned to her and smiled sweetly. "Gee, Patsy," I cooed, "It's awfully hard to play when you recite the chords so loud. Maybe you could just mutter them under your breath, and you'd still be able to keep up with us!" I smiled once more, and turned back around to the piano.

She NEVER did it again!!