It's weird to me that people can have a difference of opinion on how good an actor is. For instance, I think Sarah Michelle Gellar is fucking awesome, but an acquaintance thinks she's terrible - can't act to save her life. Wouldn't you think this sort of thing isn't negotiable? Either an actor can convey an emotion or they can't, right?
But today I realized: the audience has different levels of perception. I bet that's where the issue lies.
I mentioned a while back that I seem to fit the profile of a Highly Sensitive Person - and one of the strengths of an HSP is that we're very attuned to the emotions of others. So maybe I can pick up on it perfectly well when Sarah Michelle Gellar emotes some complicated thing like Being Secretly Attracted to Her Arch-Nemesis While Realizing She Might Have Left the Oven On, but other people don't see what she's conveying because they're bad at sensing emotions in general. "Subtle" probably comes off as "wooden" to them.
It all makes so much sense now!