It's weird that you put so much value into whether someone watched a show or not.
Some shows are so same-y I will go "no, I haven't watched it" only to later remember I did, sometimes absent-mindedly or not very invested, or "oh yes I have" until I remember for whatever reason I was going to watch it but didn't. It's just... not that important, for me, whether I have watched a show or not. I have watched millions of shows and not watched a bazillion. It's just not that important.
If you ask me "are you a fan of the thing?" I can answer more accurately, because it's either "yes let's talk about it" or "no".