Anohana the Draid

Anohana is a really good anime. The plot is good and intriguing, and all of the characters develop and change.
After one of their best friends died, the five other friends slowly drifted apart and became hostile towards each other. Their friend comes back to have a wish granted before being reincarnated. All of her friends feel guilty about her death, but eventually they put their selfishness aside to help grant Menma, the dead friend's wish. Along the way, all of them become friends again.