I've been working on a presentation for work about silent films (not in any way relevant to the job, but I was asked to do a presentation on something fun so I figured what the hell), and it's caused me to really appreciate The Cabinet of Dr. Caligari even more. I already love the movie but really analyzing it it's clear that the range of performances on display is fantastic. Conrad Veidt as Cesare is so stilted and zombie like that he was probably the prototype for Frankenstein and the zombie genre at large. Werner Krauss as Caligari is just so creepy and decrepit that he's every mad scientist at once. Even the "normal" characters that are just regular people emote so much and portray fear and insanity in such a terrifying way.

F.W. Murnau (actually it was Robert Wiene, I mixed him up with Murnau since the latter did Nosferatu) knew that the acting had to be able to carry itself just from facial expression and physical presence alone and he got some damn fine work from his actors.

The movie is in the public domain, so go watch it! There are a lot of great restorations out there.