Reminds me of the confusion with negatives and languages:
-Vill du inte ha glass? [Don't you want ice cream?]
-はい [Yes]
Does she want ice cream? Answer: No, she doesn't. I added a not, so she's reversing the answer as Japanese people do.
The number of times I've been dumbstruck by this is larger than I'd like to admit, and I'm a coder.