More than a few times. I've learned not to make hasty judgments.
Isaac Asimov wrote that he visited a friend in NYC and to get to the man's apartment he had to pass a group of young men who, he said, looked like street thugs. He worked up his courage and hoped for the best but as he tried to walk by one of them took his arm.
"Aren't you Isaac Asimov?" asked the lad. (His appearance was as distinctive as Albert Einstein's and his face very well known.)
"Yes I am," he said.
"Hey, that's great. I've read all your books."
And Asimov concluded that he was a "fine young American".