Related, I'm sure many people here know this, but it's super useful for those that don't. To undo any uncommitted work and go back to the original state of the branch use: 'git checkout .'
I like doing a 'git stash' or 'git stash save deleteme' instead. That way if I realize a moment later that I needed anything, it's still available (if I haven't done a 'git stash drop' yet).