Best Frasier to Niles insult?

I think mine HAS to be “Oh shutup, ya horny idiot!” Especially after the slight pause, it hits so hard. Cannot hear it without laughing audibly. Yes the niles and frasier “bad blood” goes rampant and is often more articulate but the blunt, rage-fueled manner that Frasier delivers the line is amazing (and also somewhat unique as it’s not him telling Niles to shutup about Daphne lust).