I've just rewatched Rickternal Friendshine Of The Spotless Mort and man, the facial journey that Memory Rick goes on when he sees Rick's rejection at Blood Ridge is truly a masterpiece. His expression gets more and more dejected, and he finally settles on the deepest frowny face I've ever seen animated on a Rick. Hoe's mad lmao.
I also love that Memory Rick's dialogue goes from "Best friendship ever!" to "I get it. It wasn't the battle that went wrong," and Rick's only response is "mm-hmm."
Also!! I never noticed before but Roiland pitches the memory Rick voice a little higher than current Rick's voice. It's subtle enough that I only just realized it, but it's a nice touch.