Comment by plorg

Or when you try to unsubscribe from a mailing list and are prompted:

  Unsubscribe from the following:
  [X] List A
  [X] List B
  [X] List C

  [ ] Unsubscribe All Lists

But if you check the "all" button it clears all of the individual ticks.

I would say a solid 80% of unsubscribe prompts have some sort of similarly confusing layout or verbiage.