I'll go ahead and assume the question is referring to my sanity, not questioning whether or not I'm angry.
But I'm angry.
There's a myth about sanity, that if you question whether or not you're sane, then that's proof that you are in fact sane.
The truth is that everyone, sane or otherwise, questions their sanity from time to time. And the beauty of that is, most don't ever go into great detail about what kind of intense nonsense is in their own heads, so they have no idea what to compare their crazy thoughts to.
For example. "I think about drowning elephants a lot, but I have no desire to choke someone to death. I'm weird, but I'm probably not crazy."
That person doesn't really know shit. For all they know, thinking about drowning elephants is the craziest thing a human could possibly do.
Tasting feces. I think that's the best barometer. If you like the taste of feces, you're probably crazy, if you don't, big surprise, feces taste gross and you're normal.
Ah-ha! Busted with a turd in your hand! Don't eat feces! That's crazy!
See how complicated this can be?
Short Answer: I love when Prince asks me questions.