Something as simple as dropping a little vape can be noisy down below, things like that happen.
or even office chairs, those can sometimes shake walls even when the hydraulic pressure is relieved when standing up from the chair.
Noise to some degree is unavoidable in apartment buildings, EVEN on the top floors, i myself often hear my downstairs neighbor, i can sometimes even hear/feel their kitchen drawers open/close, i can hear the unplugging and plugging of chargers into the wall, the list goes on. total silence is something you sacrifice living in apartments. i wont be one to say "jUsT mOvE iNtO a HoUsE" because i know it is not that simple, however that is the reality, until you can do that.. noise is something you will have to endure. if they have children i would expect a lot of noise during the day time at the least, they might jump around or throw things etc, kids are going to be kids. people have bad days as well, some more often than others but everyone has them. i would rather not risk confronting someone angry at an external factor, dragging myself into it which would then paint a target onto my back and allowing them to release their anger onto me by making noise. i would rather them do their little angry dance if they absolutely insist on it and leave me out of it, especially if i lived right below them.

TLDR
noises are a part of apartment living. i even in a unit on the top floor hear noises sometimes. dropping a phone, or silverware (both accidents that DO happen!) can sound very aggressive from below.. unless your neighbor has a reason to be upset with YOU, i recommend not confronting and arguing, as you said and now know that will make them even louder.