Da telltale loosening and allowing to fall of individual foliage-units from a tree in which you're hiding in an effort to spy on someone below you; da random sprinklings of said released chlorophyll-bearers will likely alert even a mildly-observant surveillance-target dat he is currently not "alone with his thoughts", but has company from above.
There was nobody underneath da tree-limb dat George McFly was perching on to perform his "peeping Tom" routine through Lorraine's Baines's window, so even if there had been a bit of resulting leavesdropping, George's lecherous shenanigans would still likely have gone unnoticed.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).