I recently bought a new TV, and out of excitement left it uncalibrated. First film we watched was live action, which I don't watch much of, and it looked fine to me. The second film was anime, which I watch a lot, and I could tell that something was wrong: characters seemed to morph rather than move, like a bad Flash animation, and quick movements like mouths during speech seemed to lack their usual snappiness. It was only then that I started futzing with calibration settings and realized interpolation was a default. While researching afterwards, I found that people watch more live action than cartoons have a very different experience -- when cartoons were mentioned, it was often to say that motion interpolation looks fine to them there but bothers them when watching live action.

Perhaps obvious, but opinion of both 48 vs 24 FPS and motion interpolation seems to have a lot to do with expectations we’ve built from watching previous films (e.g., I watch so little live action that I was oblivious to the frame rate change there). I feel like that’s something people overlook (even in this thread) when they talk about these issues; 24 FPS isn’t better per se, it’s just that if you watch enough stuff intended to be played at about that frame rate, anything significantly higher starts to look wrong.

(Irrelevantly, a cool anecdote about motion blur: it’s what led Spielberg to prefer CGI dinosaurs over stop-motion techniques for Jurassic Park. Although animators were producing some fantastic dinosaur models, the lack of motion blur still left them feeling unnatural and out-of-place on film.)