The loss of Robin Williams continues to send ripples through show business as the comic's contemporaries ask what everyone else is asking: Why?

Grieving and wondering what they could have done to help the brilliant comedian and actor is eating away at his famous friends. While it was public knowledge that Williams made a planned stint in rehab for drug and alcohol abuse, no one knew the depths of which the comic had sunk. Desperate and alone, Williams took his own life last week, shocking the world.

Late night king, David Letterman, gave the late Williams a touching tribute during his broadcast on Monday night that had fans reaching for the tissues. Letterman regaled in a story about performing with Williams at the world famous Comedy Store on the Sunset Strip back in the '70s. The host talked about how seeing Williams' act was unlike seeing anything he had ever seen before.

The pair had a 38 year friendship and Williams appeared upwards of 50 times on Letterman's broadcasts. The late Williams even gave the unknown Letterman a bit part on his '70s sitcom "Mork and Mindy."

When Letterman saw Williams perform, it changed the way he saw comedy. Robin was just that good.

"It was like nothing we had seen before. ... We're like morning dew and he comes in like a hurricane. ... We didn't approach him because we were afraid of him. Honest to God, you thought holy crap here goes my chance at show business... "