What is the Best and Worst Documentary you've ever seen?

The BEST documentaries are between "This Is It", "Paris Is Burning" and probably "Fahrenheit 911" and the WORST is probably "Super Size Me". I like documentaries, and I have seen plus good ones than I have bad. I didn't like "Super Size Me" because I thought it was dangerous to do and didn't offer me anything that I didn't already know.

I'm not all that into documentaries...

I don't know if I can name that best documentary I saw. I CAN name the worst though, which is Cosplayers: The Movie.

Cosplayers: The Movie doesn't even spend a single seconde talking about cosplaying. All it does is discuss about anime, conventions, and voice acting.