In those situations I just reciprocate the gesture.
Aw come on! A guy’s gotta air the balloons, fer cryin out loud!
Anyone trying to commandeer the muzak.
Juice monkeys plying their wares.
Something depressing about the Original Universal Gym. Not the more modernized “sections” that would comprise an original, but the original itself, which, IIRC, was ubiquitous in just about every educational/sporting institution from about, say, the 60’s until, say, I dunno - mid 80s?* Perhaps I’m subconsciously making negative grade eight associations of having to go through “the circuit” (yes - that goddamned circuit you had to follow on this big wall chart with colourful graphics), having to wait in a dreary, cold, weight-room mini-line-up to go on to the next weight exercise.
*Heh - and then the Nautilus machine took over? Or maybe I’m getting my time-lines mixed up.