I'm known in my gaming group for doing things that aren't necessarily overpowered but surprising/unpredictable/crazylikeafox. My DM would argue that I'm twisted and insane for doing things like having a quickened Prestigitation ready for a bad guy who got turned to dust after being defeated in battle to make sure that if he comes back, he's staying with us >=D
I made my character's personality quite professorial, unaware, highly academic/theoretically predisposed, family oriented, and staunchly Lawful Neutral. As such, he's sorta like a mix between Emmet L. Brown and Waldorf from the Muppet Show. We have a lot of laughs and the other party members are routinely treat him like as slightly crazy and don't take him seriously a lot of times. Even though he's exactly right about most story problems/villain plans. He just thinks about them in the most logical manner possible (he can't pick up people's motivations or deceptions in person, but he reasons his way though them like a math problem).
That said, my DM knows that my wizard could dominate the world and when I was nearly turned into a vampire one fight (wizard/sorcerer vampire) he was both delighted and shaken with all the harm he could do with him under his control (he's seen me work and I'd help him because it'd be fun!). We're all trying to be the "good guys" as much as we can but if our DM pushes us too far, I've told him things could get ugly. Ugly in that we would have to consider going to plan B.
Plan A: Be the good guys, save the world and eat pie.
Plan B: If Plan A fails, join Team Evil, dispense with silly moral quandaries, and crush all opposition brutally with the liberal application of high level arcane and divine magic.
Plan C: If Plan B fails, learn the name of an
Eldritch Abomination in the Far Realm, push my fellow wizard's caster level as high as it will go and cast Gate. No Cthulu-like monster would pass up the opportunity to come to the material plane! If he destroys the other BBEG (sorta an Eldritch Abomination himself) then he can have the planet. The bad guy cult will suddenly become the good guys who are trying to save the world from being devoured so it can be conquered! Then, once the fighting is just over and we have a winner...we swoop in and kill the winner with
everything we've got. Win the game.