Paint was always such a shit that many people actually called it MS Pain.
Microsoft has been fixing many things from version to version, making the one that ships with Windows XP even quite usable. Following versions were even bigger steps, with final version (Windows 7) actually rewritten from scratch, using ribbon, multi-level undo and many, many more.
Pity, that with one of the last version they removed a "small" feature that was always there -- a warning screen to warn you that you are about to loose your work...