Please DO NOT tell people to run `git reset HEAD~ --hard` on their master because they might have yet untracked files about ohshitgit HOT 1 OPEN

I would suggest a cleaner solution of keeping the original instructions, but replacing --hard with --keep which is the safer version of hard that aborts if you have any local changes that would be lost.
Doing this would avoid the danger of loosing un-commited changes, but still keep the relatively simple 3-step workflow described.

Relevant snippet from git help reset:

--keep
               Resets index entries and updates files in the working tree that are different between <commit> and
               HEAD. If a file that is different between <commit> and HEAD has local changes, reset is aborted.

from ohshitgit.