I mostly love git, but I can never remember the syntax for undoing and reverting things, which is partly because I don't use it that often, and partly because the syntax is un-intuitive. I'll update this post as I hit the various scenarios.
Merge broken by conflicts
Often I'll pull in changes from the stable repo, forgetting I've made some uncommitted local changes, which results in a conflict. To drop all of your local uncommitted changes: