Crumb is great, Some Kind of Monster is a total pisser but my favourite documentary by FAR is...
The Devil and Daniel Johnston
it's really sad but it's also really quite moving and really hilarious in parts.
Hearing Daniel call the Mountain Dew HQ from a mental institution to sing them a song he's thought up for their new advert which just ends up with him screaming "DEMONS!!! DEMONS!!" is completely amazing.
Or the scene with Sonic Youth driving round the streets of NY looking for him.
Or Gibby Haines being interviewed in the dentist's chair about Daniel taking LSD and going nuts.
All priceless.
Best documentary ever. End of thread.
