I'm wondering if anyone else feels, well, not surprised about this. Sudden passings are always a surprise, but the suicide part isn't so much. Robin was always one of the more eccentric figures in Hollywood. Every interview I ever saw of him was basically 80% or more of him performing impersonations, making voices, and cracking jokes, as if he felt like he needed to. But really, he could have just sat back and talked.
As someone who knows the desire to get people to like you through a funny mask, I could pick up on it immediately. I personally don't do that all the time and it's certainly not all I am, but I felt that that was what Robin was. Due to the frequency he was doing it, I always figured that he was always putting on the funny mask because that was the only way he felt comfortable with getting people to like him. I'm really sad by this, but not surprised.
Take Jon Stewart in comparison. Funny as hell, but he can instantly become serious on real issues, and doesn't feel the need to be the talking monkey. In fact, the talking monkey bit happened when he went on Fox News and the Fox commentator said "I like you better when you're funny. Go back to being funny." and Stewart just ripped him apart.
I personally liked Robin far, far more in his dramatic, serious scenes. The scene in Patch Adams where he is crying with his head on the casket of his girlfriend or wife is heartbreaking.