At the last apartment I lived in, I thought the people in the unit below me were constantly running an unbalanced washing machine, as I would frequently hear this loud, rhythmic THUNKA THUNKA THUNKA THUNKA coming from underneath my floor, usually for hours at a time. At least, I assumed it was a washing machine, since nobody has that much stamina for it to have been anything else, I thought.
After a few weeks, I put in a noise complaint because it was starting to get irritating. When the management followed up a few days later, they told me that the tenant below me just had their ceiling fan at full speed and two of the bolts unthreaded themselves, causing it to knock around wildly. And the tenant was deaf, so she had no clue her ceiling fan was only a few days from loosening itself completely and falling apart.
It's honestly a little insane that after over a hundred years, we haven't come up with a better way to move air around a room without dangling 50 pounds of spinning death above your head.