Our children could never shut doors quietly when they lived with us and it became an annoying problem. This simple solution made a big contribution to peace and quiet (especially at night).

Stick some draught stopping foam strip along the part of the door frame that houses the latch. It quietens door closing no end. It often isn't necessary to put the strip all the way along. Just sticking it to the place where the door touches the frame first will do. It can hardly be seen if the door frame is white.

Since slamming doors is an expression of frustration it unfortunately means that the 'door slammer' becomes even more frustrated when they don't get the expected noise. I often saw (with a tinge of satisfaction) it being tried a few times before they gave up in disgust.

Do you have a tip for gates? There're two near where I live (and sleep!) that people consistently let slam behind them at 3AM. There's got to be a way to quiet that noise down, so I'm not jumping up all the time, thinking someone's shooting a gun around the place!

tip for banging gates, buy some of that adhisive that
is easy to remove, looks like putty, but comes off easy. I use it to place where my cuboards might bang into each other, being that my cuboards are on angles. I am not sure of the brand name. But there are discount types out there. Stick it where the gate bangs, should help, and not get in the function of the gate.

There is a railway crossing metal gate that we pass through regularly. It is closed by a hefty return spring. The residents have taken it upon themselves to quieten it down by wrapping some carpet around the parts that would otherwise bang together. They also appear to oil the hinges.

Mind you, it doesn't do much to lessen the noise of trains thundering past their doors.