Many actors will tell you that the most difficult roles to play are in comedies. It's not easy being funny, it's pretty damned difficult. Being funny at a level like Chaplin is a very rare thing. It's often true these comedians can portray the saddest characters extremely well too. I was just talking with ButterflyEffect about Bill Murray's phase of playing sad, broken older men. Do performers like Murray and Chapman suffer greater sadness and maladies than the average person? Some do, some don't. From what I know, Bill Murray is a pretty regular fella, loves his family, golfs, wears jeans and a tshirt kind of guy...that happens to be an extremely gifted performer. This ramble is my way of saying, "I agree that we remember the tragic because... well, it's memorable." For every psychologically abusive Chaplin there is a Murray, being equally hilarious and pathologically normal.