My first dormitory at College had been majority Hispanic. I hadn't known many Hispanics. One of the upperclassmen there, a proud well-built guy, told me that sometimes people said things to him that he didn't know whether they were being funny or over-the-line prejudicial. His rule: "If they're smiling, they're funny, or TRYING to be funny. If they're not smiling, they're insulting your race."

And of course, there's the legendary quote from Owen Wister's The Virginian
"When you call me that, SMILE!"