All the comments that "you can just use X to do Y" is missing the point that Paint just works, for almost every value of Y. No argument, Paint.net is great, snipping tool solves the grab and crop, but for most anything else you need to do in a hurry, you need a quick paint program. It's like removing Notepad: we all know hundreds of editors we would replace it with, from Notepad++ to vim/emacs... but isn't nice that…
Confirming to scale an image by manually entering a % value requires you to click outside of the value field BUT inside the scale dialog. That's right - there's no Apply or Confirm button, you just have to figure out to click there. Pressing Return or Enter doesn't do it either.
On the second open, there was a "rate this app in the app store if you like it" popup.
Microsoft's ineptitude at UX is mind-boggling.