Like all great genius minds, he had his demons and struggled with them. They said recently he had been having bouts of depression and now think it may have been related to the open heart surgery he had in 2009. Doctors are saying now this is a possibility and he should have been advised to seek help as the depression associated with OHS is very real, can be devastating, and can linger for years.
Probably one of the two best comedic minds ever, the other being Robin's own idol and mentor Jonathan Winters. Both were absolute genius at off the cuff improv, but I would have to give Robin the edge in genius. He bought so much laughter to the world, yet could play a serious dramatic role as well as anyone.
Good Will Hunting, Patch Adams, Good Morning Viet Nam, Jumanji, and Hook are my favorites of his movie work. As far as his comedy shows, I'll take any of them over any of the newer comics. Even some of his shorter improvs, such as on "Who's Line is it Anyway", were just fantastic. It was hard for anyone to follow him when he came up with a quick one-liner.
RIP, Robin. The world is a better place for having known you.