People do things differently when they think they're all alone and say things to themselves that weren't meant to be heard by others, and sometimes the things we say and do when we think we're alone become dirty little secrets.
Heck, most people don't want anyone else to know they sometimes talk to themselves, much less that they sometimes do gross stuff involving bodily fluids.
The questions on AskReddit are usually answered with funny and awkward stories, but the stuff people were seen doing when they "thought nobody was watching" (NSFW) is cringey humor from beginning to end and proves even pets do weird stuff when they think they're alone-
-Via CollegeHumor (NSFW language)