If you give Avatar a 1/10 then I envy you, cause you really haven't watched any really bad movies.
People like Avatar for one major reason. Because unlike most of the recent blockbusters Avatar was made with a professional way.
Above all the story, the visuals, the messages and the 3D gimmicks you can clearly see Cameron's experience.
It's so obvious to me.
e: I forgot. This was the first movie ever that actually transport you to another planet. Cause Cameron was clever enough to realise that flora would make the difference.