li (implied)

"?."?.

I tend to use the upside-down-smiley ( 🙃 ) if I'm being sarcastic. I don't know if that's universal. Also I realise your post might have been a joke but I have a habit of responding to stuff as though it was literal and sincere 😅

Aside: if you ever want to troll someone without actually trying very hard, just respond to every single thing they say as if they meant it literally and sincerely. I discovered this accidentally at work. It has quite funny results but it doesn't make you very popular