Not "Monster-Related", but on people "hearing" stuff:
Just last night at band rehearsal, (everyone on IEMs with individual monitor mixes), SAX player asks for a little more SAX in his mix, so I reach for the Aux send on SAX channel to dial him up a tad in HIS MIX. Simultaneously the female VOX says "oh, he too loud now" and guitarist says "that's MUCH better".
Weird because I hadn't even gotten to the knob yet! Not to mention that his mix is completely separate from theirs. Would have made some sense if I touched the gain or something, but I didn't.
Just about every time someone asks for changes in their mix, they somehow hear that change BEFORE I make it. Power of suggestion is a crazy thing.