Not exactly an insult, but it was the remark that got Groucho Marx's show pulled from television.
Groucho was asking a guest the usual questions: job, family, etc. The guest replied that he had eight children.
"Eight children?" Groucho remarked.
"Well, I love my wife," the guest replied.
"I love my cigar, too," Groucho quipped, "but I take it out of my mouth once in awhile."