You know Don Rickles as the comedian from whose sarcasm no one is safe - ethnic groups, bald-headed men, children, politicians. Rickles has built a career slashing them to ribbons with a sharp tongue. Ah, but everyone knows guys like that are pussycats offstage, right?

Not quite, Rickles began his career in Washington, where he was known as Don "Glasshead" Rickles when he performed ribald humor at the old Wayne Room at the corner of 14th and I Streets NW.

Has success gone to Rickles' glasshead? Enjoying a midnight dinner at a pricey restaurant earlier this month in Toronto (he was there to perform), Rickles was effusive with his fans; diners who greeted him received warm handshakes and smiles. "What's your name, son?" he asked one youngster, whom he then twice admonished, "Take real good care of your mom and dad, you hear?"

But Rickles was less charming to his tablemates - his manager, his secretary and an elderly black man whom he introduced as Joe, "my companion and friend."

Midway though his steak, Rickles asked Joe for some packets of Sweet 'N Low to give to two nearby waiters, jokingly, as tips. But Joe found only a few packets of the artificial sweetener in a leather bag he carried, and Rickles flew into a rage.

Pointing his finger at his assistant, he said, "That's your job - I want you to go out tomorrow and buy two boxes. Do you hear me? That's your job!" He repeated the command to his secretary - "Get lots of that stuff. Are you listening to what I'm saying?" He continued to glower at his dinner partners until his coffee cup was refilled, and Joe began fumbling through the bag for more Sweet 'N Low. He eventually found one packet, a discovery that Rickles greeted with, "You're damn lucky, buddy. I was just waiting for you to say you couldn't find one, I was hoping you couldn't."

His sullen employes agreed to make a major purchase of Sweet 'N low the very next morning.

Footnote: As Rickles might say, everybody is a comedian. He asked that his steak be charcoal-broiled on the outside, pink in the middle. As a gag, the chef sent out a plate on which one charcoal briquet rested. Rickles, the chef should be relieved to hear, laughed.