Just over a week ago, the originals band played a gig, and the second half was somewhat sloppy. So this evening, first rehearsal after the gig, the BL (singer/songwriter/guitarist completely unafflicted by the ego that one might expect him to have) comments to me that I sounded a bit dodgy on song X (I agreed, I played mostly the right notes but a few were well off), then he said to the drummer that there were a couple of songs that had slight issues - one was too fast, and in the other the drummer had started putting in a fill, the timing of which was throwing the guitarist. He wasn't making a big deal of it, just saying which songs we needed to look at and why, which was perfectly reasonable (he'd also apologised on the night for missing a line on one song which had thrown me briefly, so he's happy to acknowledge his own errors). The drummer took umbrage, which we thought initially was him joking about it but no, he went off on a rant about taking this criticism personally, packed up his sticks, pedal, cymbals, and snare, and stormed out, leaving the remaining three of us (me, BL, and slide guitarist) somewhat open-mouthed.
Not sure whether he's definitely gone for good, but with a gig coming up on Friday which we don't want to cancel, the slide guitarist who also plays drums is going to step in and we'll be back to a three-piece.