Funny: I didn't even like the film so much when I first saw it. I thought it was just to 'plain'. And I'm always overwhelmed by images, especially in IMAX, so I couldn't even really enjoy its visuals und back then I didn't quite grasp, how groundbreaking all the new technology and motion capture stuff was. Though I remember I almost cried during Graces last scene. That usually doesn't happen with a blockbuster, but I almost immediately forgot the film for nearly 8 years. Then, a bit more grown-up, I discovered the movies of James Cameron again and saw them on a whole different level, including Avatar. Thats basically why I'm here.
But I never suffered from post-Avatar-depression, thanks to god. Now the movie hits all my emotional nerves whenever I watch it and this can be quite exhausting.^^

I believe that the "depression" feeling myself and some fans are getting is directly related to their love scene under the Tree of Souls. The pair's relationship build-up of Jake being taught by Neytiri to hunt, capturing his own banshee, then being initiated into the clan as one of the people is finalized by the bond between their queues.

The unmatched mental, emotional, and "Physical" connection is ultimately achieved here that we as viewers yearn for on this entirely new level.

For me it was the world they live in that made me depressed because I was just "another human" on this earth and not in harmony with nature. The movie changed the direction of my life and made me more connected to the natural world around me. I never thought growing up that I would be an avid gardener and Avatar is what brought that onto me. To see a plant grow from a seed into a fruit producing specimen and feed me is quite amazing. This same plant gets full respect when it dies: it gets buried in the garden to give back and become one of the "plants".

Funny fact is I have not intentionally killed a bug since I saw this movie. I let them all out the windows to where they belong. I feel every living organism has a role and I should not disrupt it.

I just watched Avatar this week on a brand new Qled 4k tv. Holy damn does it look good!