Roommate changes Wi-Fi password after his roommate refused to pay his share for 3 months 'He flipped out, saying I was sabotaging his online classes.'

Look at that! If it isn't the consequences of his own actions! 

You have to put a lot of faith and trust in your roommates. You must trust that they aren't sticking your toothbrush in the toilet every morning after you leave for work. You have to trust that they won't eat all of your groceries and pretend that they don't know anything about it when you confront them. Most importantly, you need to trust that they will pay their rent and bills in full and on time. 

In past roommate situations, we've all been responsible for paying our own portion of the rent on a rent portal, so the landlord can see exactly who has paid and how much they've paid. My current landlord wants us to Zelle him the rent in a lump sum, which has worked thus far, but could go horribly wrong if one roommate were to stop paying rent. The roommate who sends the money might be forced to use their own funds to make up the difference because they don't want their housing situation affected by one bad apple. That's the problem with having a ton of roommates: you're relying on way more people to be responsible than you would be if you only had one roommate or were living by yourself. But even having one bad roommate can make your life a living nightmare. Imagine what kind of financial pickle you'd be in if your roommate stopped paying rent and utilities for six months? You'd either have to jeopardize your living situation by not paying the rent and bills in full on your own dime, or destabilize your personal finances by draining your emergency fund and even going into debt for a roommate, of all people.