Sad ending

I got to see this movie just recently. I found the ending sad because at the end of the movie Robin Williams is ready to leave the set and he is offered drugs and he just walks out. You see him walking out to a bigger and brighter future and you feel he is going to go straight and he will go on to be great. He did go on to be great, but his inner demons got the better of him and he commit suicide later in life. I've read that the reasons for his suicide were battling depression for years and alcoholism. It also came out that he had Parkinson's. While the movie had a happy ending, it was very sad knowing that Robin's life didn't. Robin Williams' life met with a very very sad end. Every time I see one of his movies now, I still can't believe he's gone and the way he died. When I first heard the news, I was shocked. When all of the details came out, I felt even worse. It was so horrible.