And of course if you make normally inanimate objects smart enough to talk, you should expect your players to want to reason with them and convince them to do what the players want them to do. Gary Gygax, in his infinite wisdom, included a mechanic in the original edition of Advanced Dungeons & Dragons specifically to prevent PCs from reasoning with intelligent magical swords: the Ego score.

Basically, the more powerful a sword is and the more useful it would be for a PC to be in control of all of the fantastic abilities it can grant, the more Ego the sword has, the less likely it is to acquiesce to demands to use those abilities, and the more likely it is to talk back and be generally annoying at the worst possible moment!

Is that the perfect game mechanic or what? Gary, we are humbled by your boundless game mastering genius.

Transcript

Obi-Wan: Wait, the missiles are intelligent? I use Force Suggestion.
Obi-Wan: "These aren't the ships you're looking for."
GM: Droids are immune.
R2-D2: Oh yeah, baby.
[SFX]: < bippity bedoop >
Obi-Wan: Look, er, missiles... Can we discuss this?
[SFX]: Whoooosh!
Missile 3: We're always receptive to suggestions.
Missile 4: Heh, heh.
Obi-Wan: Okay. How about that dreadnought over there? Wouldn't that make a juicy target?
Missile 4: No can do, dude.
Anakin: Why do you even want to hit us? That would end your existence too.
Missile 1: Live fast and die young, that's our motto.
Missile 2: Testify, bro!
[SFX]: Whoooosh!
Obi-Wan: You don't need to be evangelical about it.