Back when Robin Williams first debuted with "Mork & Mindy", I wasn't one of his biggest fans. I had read reports of his rampant cocaine abuse, and mostly because of that, shyed away from anything he did. I also was never a fan of people who were "on" all the time...always trying to impress or be funny.
It was only after his dramatic roles in movies that I started to really like him. Below the layers did exist a genius. And apparently, he was a very good person.
Here's a video that shows him in a rare moment. Making himself happy...interacting with an amazing creature.