I thought about posting this thread while dragging a window around macOS funnily enough. It seems that it makes intelligent guesses on whether you are trying to place windows near each other and ‘snaps’ them into place if it thinks you are - it’s ever so subtle - so subtle that it’s barely noticeable, making it feel very natural (thus, perhaps more importantly, also making it void of any frustration which might be the case were it was poorly implemented).
So that got me thinking - what is it about each OS that makes it unique, or, in your view, what makes it worth using over the others?