Oh you wouldn't believe the extend these people will do

My babi upstair neighbour, after I complained his door hinges creaking too loud, now purposely open/close his door few extra times especially after midnight

seek a lawyer and send him a LOD.
some people afraid to deal with the law eventhough you didnt have a case to win.
so the dude may chicken out to avoid trouble to hire a lawyer to defend himself.

Next, maybe get a police to help.
imagine a police telling you " kawan saya mahu tidur lena lepas 11 mlm, kalau hang buat bising lg, hang pikir lar sendiri lain kali i dtg".
Most people do not want to cari pasal with police on a personal basis.
Calling police to raid him and getting a police (your friend) to warn him can be 2 different effect.

wat la, when u unscrew the pipe, the shit will flood ur toilet first

Hi all, Normally the floors between condos are made out of concrete right? If the units are separated by a layer of concrete, how can you still hear people walking around?

Not sure if some condos have other materials instead of concrete between floors. Have a friend staying in a condo, he owns a subwoofer, and when he plays music or movies, he don't seem to get any complaints from neighbors. I would imagine a subwoofer to produce more vibrations and sound compared to footsteps right.

your statement seems to remind people to be afraid of lawyer or not to mess with lawyer, even though you are suffering.
remember you hire a lawyer yourself.
what makes you think your own lawyer is inferior to him?