These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternative Character Interpretation: In the 1992 movie, Curley's wife is far more sympathetic than in the book - specifically, the scene in which she crosses the Moral Event Horizon by threatening to have Crooks lynched is omitted. The director wanted her depicted more as a "sad angel" rather than the vampish character she appeared to be in the novel.
Steinbeck once wrote to the original actress portraying Curley's wife in theater that she was sympathetic
Squick: Curley's glove. It's not that it's full of Vaseline, it's that he's using it for his wife.
Weird Al Effect: George and Lennie are far better known to modern audiences as characters regularly spoofed in Looney Tunes and Tex Avery cartoons ("Which way did he go, George? Which way did he go?") Tex Avery even made a cartoon based on the character Lennie called "Lonesome Lenny".
The Woobie: George. The man constantly loses his job and seems like he actually is a pretty nice guy, but he has to endure a lot of pain since he travels with Lennie. He causes George to frequently lose his job and be on the run and George can't have a social life because he always has to take care of Lennie AND he forcedhimself toshoot Lennie. You gotta feel a LITTLE sorry for him because of that.
Lennie, too. However goofy it may be, the scene in which he gets internal dialogue (with the aunt who raised him and with a rabbit) is utterly heartbreaking; he blames himself for everything that goes wrong in George's life, and his biggest fear is being abandoned. And all he really wants to do is hold little animals.
Curley's wife, to an extent. She's married to a badly-tempered man who is extremely possessive of her, and keeps her as a trophy wife. She's obviously lonely, but all the workers are too scared of her husband to speak with her. She later tries to chat up Lennie, which ends with her panicking when he won't stop stroking her hair and, when she starts to scream, him killing her by accident.
Quite surprised that he isn't on here but most definitely, Crooks. He's a lonely black man that isn't allowed to befriend the other workers because of his race. He receives no respect despite being one of the few, at least we know of, who one lived on his "own" land. He's now jaded due to racism and loneliness, explaining his attitude toward Lennie initially.