Kai and Arte and their friends, comparing notes about their similar experiences with... any set of goons, really: "Yeah. These guys just NEVER learn, do they? I mean, how many times can you fail at trying to take over the world AND STILL KEEP TRYING? Every week, it's the same thing. Gotta give them points for determination, but... Sheesh."
In other words, it's just the goons being stubborn. And not terribly creative with their Fiendish Plans.