That's my whole point! The context and expectations seem pretty obvious to you, doesn't it? Why then are you surprised that a different culture has an equally obvious (to them) fixed answer ("Yes") to any question asked by someone with power/authority to their lesser? Both depend on mutual learned cultural awareness, and can fail spectacularly in cross-cultural contexts.

Edit: my regional favorite is "We should meet for lunch some time" which just means "I'm heading out now", but you have to decode the meaning from the nature of the relationship, passive voice usage, and the lack of temporal specificity.