Don't ask "Did you finish task X". Ask "what did you do on task X?". What you see as finished and what the other person sees as finished might be separate things. Maybe you see 100% unit tested, reviewed and documented as finished, and the other person means feature complete, but untested, undocumented, not reviewed.
Open questions allow you to see what the other person understands. In some cases they might misunderstand your question entirely.
another is that strange indian head-shake that is so hard to reproduce - never figured it out completely, but it felt like when I eventually ask yes/no question and they say yes with that shake, it's actually more like no/don't know/maybe
So you are 100% wrong when you say "The answer to Y/N question is always yes in India".
Which makes me doubt/ blindly ignore any of your opinion ever.