When you initiate action like delete, you might be thinking “yes/no” in the moment, but you couldn’t possibly argue that “cancel/delete” is less intuitive or breaks flow.

And we don’t always react to confirmations instantly. What if you’re distracted away, or you suddenly second guess your decision and perform some auxiliary research? Or what if you have more than one dialogue box on the screen at a time? From a UX standpoint, it is far safer to repeat the verb rather than use a generic.

To be frank, the only reason why I could imagine using generics is laziness.