I disagree with people completely about the characters not growing. They were all damaged people. And they needed each other and Greendale because they couldn't function outside.
But we saw each of them come to terms with this and with themselves and the people around them. And they learned not to be ashamed of their identity, but learned to be comfortable with it and find that they were fine all along.
Troy, Annie, and Abed, all really grew the most over the series as they discovered who they were. Troy especially after his 21st bday in season 2 when he saw what adulthood really is, and he gravitated toward taking charge and being a leader in that seasons finale. Then taking his own path in season 5. Leaving Abed to mature without him. Abed was really psycho-analyzed in season 3.
Jeff grew so much too. There was always this push and pull with his age and imagination/nerd culture which he repressed. It's all there. Just look at the end of Pillows and Blankets, where he goes to the deans office to pick up Troy and Abed's imaginary hats. It's all there guys. It doesn't need to be spoon fed. You just have to look for it. It's what makes Community the best. Same with GI Jeff, his fear, and acceptance of aging. Or the finale with unlocking the computers door with his love for everyone.
Britta committed to being herself even if it caused her scorn. She's a hero as well. Pierce became more accepting of other people, and understood the power that Greendale had, and what it did for people. The whole show is about healing and learning and acceptance and growth, but above all imagination.
Also season 3 and 5 are amazing. And perhaps my favorites.
I seriously tear up thinking that it's probably all over now. Greendale is where I belong.