"Every crowd is different, and having that kind of go-with-the-crowd kind of moment is neat. Nothing's set in stone, so if you're not feeling a certain number you can switch it out," said Bob McDonald about cabaret. He is performing this summer at Signature Theatre. (Courtesy Signature Theatre)

"Every crowd is different, and having that kind of go-with-the-crowd kind of moment is neat. Nothing's set in stone, so if you're not feeling a certain number you can switch it out," said Bob McDonald about cabaret. He is performing this summer at Signature Theatre. (Courtesy Signature Theatre)