I hate the multi desktop stuff.

Drag a window to top of screen and it doesn't snap full screen fast enough or consistantly.

Doesn't like to display 1 window across 2 screens.

Sometimes a window will shoot off to the side past the visible desktop for god knows what reason.

You can't nativly set up the mouse scroll to work in reverse direction to the touch pad.

I'm still not sure how to uninstall things.

When my headphone cable is plugged in and I turn on the Mac it insists to make the boot sound though the speakers as an advertizment to the world that there is a Mac around.

If I click x on a browser or app, it doesnt actually shut the program, it just minimizes it.

I can't easily see the size of hard drives/folders and how much space is left available.

Files are just scattered willy nilly in a folder instead of snapped to a grid unless I set that folders defaults...per folder?! Instead of across the whole OS

They are my personal top of mind gripes.