A killer when the hands are both on the keyboard: some dialogs can only be cancelled/confirmed with the mouse. For example, when discarding a file, you get a confirmation dialog with OK and Cancel buttons. I'm sure there are others, but I'm not in a position to provide anyone a comprehensive list. I'm just reporting the problem at hand.

Anyway. The OK button should be pressed when hitting Enter, and the Cancel button should be pressed when hitting Esc. Additionally, either button should be focused, which will be pressed when hitting the spacebar. This is default Windows behaviour for confirmation dialogs, and default behaviour for most OS'es, afaik.

I'm not sure why this functionality has been stripped out, but I'd like it back please.