My pet user interface hate

I really hate those buttons that are labeled, "OK" or "Start" or something and then turn into a "Cancel" button once whatever it is starts.

Invariably, I click on the button and the program is busy, off with the qubits, so I click again and then the program wakes up: yes boss, start it is, OK, we'll start, oh wait a bit, you want to cancel, Yes we can do that, OK cancelled. Grrrr.