This is my Favorite Keaton Film ....
It shows all of Keaton's talents - both as a filmmaker and an actor plus I love the theme. The movie reminds me of my favorite quote from Keaton, which he said that his films were his daydreams and "all the fairylands of the world" were there to be explored. Sherlock Jr tells of the restorative and therapeutic power of dreams. Anyone reading this most probably knows that Keaton's personal life was, in many ways, unhappy and I believe his films were a healthy bit of escapism and a way to work out his problems. What wasn't working in real life - worked out in his films.
I also love the ending and his interaction with his girlfriend which displays the subtle beauty of Keaton's acting ability. When she comes back and apologizes, of course he's happy, but he's also very hurt that she didn't support him when he was thrown out of her house. Subtly, I believe, you can see that conflict, especially when he considers if he's going to kiss her and when he puts the ring on her finger (again) he gives her a look that I believe he's saying to her "can you keep it on your finger more than 5 minutes this time". This is in keeping with Keaton's personality on and off screen. He was very quiet and polite, but that didn't mean he didn't have angry feelings, he generally chose not to show them.