Thoughts on One Flew Over the Cuckoo's Nest?

Just finished this movie. Thought it was okay, nothing special. I always cry and feel emotional at movies, but I didn't feel any real attachments to any characters in this movie, so nothing made me sad, or feel much of anything really. The characters didn't feel fleshed out, and even over 2+ hours, I never developed any sympathy for anyone. Especially not the protagonist, Mac. I also thought they didn't do the Chiefs character justice, and I didn't buy his evolution from being faking mute and no desire to leave, to suddenly talking and wanting to leave, all over the course of his 12 total lines.

Maybe an unpopular opinion, but imo it was just an okay movie, wouldn't watch again, was kinda bored throughout. The ending wasn't impactful on me. Thoughts on the movie?