I think the most common form of this is trying to amplify or modify farts and burps, at first to amuse yourself. But it soon becomes just the way you live your life, constantly ripping the loudest, angriest farts you can muster. Bitter farts that are clearly compensating for something. Burps that can crack a window pane and make neighbors come around to find out if you're OK, since they thought they heard a large bookshelf filled with encyclopedias collapse to the floor.
When you're doing it in an empty house, it's fine. Weird, but fine. But over time, it starts to develop into habit -- reflexes so ingrained that you will confuse them for normal. And trust me, after enough time, those burps and farts will be busted out when other people around, which only magnifies their inappropriateness.
But those weird reflexes manifest in other weird ways. For instance, in an effort to save time, no matter where I was in my apartment, as soon as I acknowledged that I needed to pee, my dick came out. If I realized I needed to pee while I was in the kitchen eating ham in front of an open refrigerator, instinct would whip my penis out like I was flashing the orange juice. Was it efficient? Yes, absolutely. It shaved precious seconds off of my pee time. But that's not the point.
It's the kind of thing you get used to when you've got no one around to remind you that you must abide by the tough but fair semantics of bathroom law. Yes, it's all just rooms, but dignified humans wait until they crossed the threshold of the bathroom door before exposing themselves. Only creeps do it while holding ham in the kitchen. I did it so often alone that on a couple of occasions, I had to stop myself as I was starting to unzip 20 feet away from the bathroom while I had guests over. One of those times was as I stood up from the table during Thanksgiving dinner with my family. I was a few zipper teeth away from flashing my mom and my delicious turkey. Thanks, lonely reflexes!