Diff dirty working copy with HEAD

Have you ever used TortoiseGit and loved the visual diff of the copy you are about to commit?
...or do you ever want to pull a small snippet of code from HEAD without destroying all of your changes?

git difftool launches your normal mergetool but running a comparison of your dirty working branch to the HEAD of your current branch.

As expected, you can diff separate branches via

git difftool branchA..branchB