I replied to this a long time ago and there's 250 posts, so I have no idea if this was said before, but I just paid attention to a problem that I have a lot, that others probably have. Not suggesting a solution, that's your job WT, just the problem (which if I were you, that's what I want to hear).
Windowing software (particularly the PC, but IIRC, also the Mac) commonly uses a technique where the cursor changes to indicate a behavior that only exists as you hover over a spot. In particular, changing the size of a pane within an application window. Corner resizing. Any drag & drop action on an object. Problems are: (a) getting the cursor icon to change by oh-so-precisely hovering over the target, (b) starting the action, say with a mouse press, while still over the target, and (b) getting to where you want to go.
I find this as frustrating as any other mouse behavior. It'll get worse as I get older, but frankly I have good coordination and this drives me nuts. Please make a mouse that fixes this.
Okay, I said I wouldn't do this, but ... my suggested solution, which you should duly ignore, is some way to slow the movement down when you're in the vicinity of a target, and then speed it up after you've captured the target with a mouse. If it could be automatic, all the better, e.g. slow down and on mouse press, automatically back to normal. Or sense a cursor shape change and when that change happens, let it linger a bit (although that starts to interfere with a software designer's choices, so personally I think that's wrong.)
Anyway, just had that thought and wanted to pass it along.