Can I interpret that “oops” is for when you yourself make a mistake and “oof” is for when someone else has a slip up? Do they share same origin? They seem awfully symmetric.
The Free Dictionary defines oops as:
Used to express acknowledgment of a minor accident, blunder, or mistake.
Oops! I forgot my library card at home.
Merriam Webster defines oof as:
used to express discomfort, surprise, or dismay
Oof! She just dislocated her shoulder, is there a doctor?