Did a TATL in J recently. When deplaning, thanked FA at exit (not SD who stayed in J). She had not been working in the J cabin but it was obvious where I'd been seated, not that it should matter. What I got in return was a grunt and someone who continued to stare at the floor. If it had been a complaint, can't begin to think what the response might have been. Glad she wasn't in J for the actual flight. Bad hair day, I guess.