Jane, I haven't done that sounds like you haven't done it yet, but you plan to :) The perfect here (as we discussed before) is emotive - the speaker is angry that someone spilled coffee. In a neutral sentence, we use the simple past.

Uly, thanks a lot for all the comments, it does help indeed, though this damned emotive perfect always drives me crazy! How come I made the same mistake again! 😤
So if the speaker is disappointed, irritated etc., we use perfect. And in case we just establish the fact (coffee spilled on the floor) we use simple past?

Bingo!

Mind you, in England I think they would use the perfect in that situation. To me it sounds emotional because I'm American. So it's not incorrect, it's just not what I would say.

OK, I got it. Thank you!