I remember playing against several computer players on a huge map. I can't remember who I was playing as. Probably either Britain or America. But I remember Gandhi approached me as an ally early on. He then pulled me into conflicts with all the other civilizations (damn, that NPC was bloodthirsty!), and together we fought and destroyed each of the other NPCs.

I over-extended myself a bit far on the last of those opponents, and he decided that was the perfect time to attack me. I knew he would at some point, since it's part of the game. But I was so angry at the timing of that betrayal.

I fended off the Indian civilization's attacks, and carefully rebuilt my resources. When I was clearly stronger than him I attacked, and hit him hard. As I ground his forces down more and more he kept pleading for a surrender. But I kept refusing.

I basically got him down to one pitifully small city that was pinned on and had no real defenses, and then played with them like a cat with a mouse. I held out on destroying them for ages, just so he could be as miserable as possible for as long as possible. Yeah, I know it was just a dumb NPC that couldn't feel anything really, but it was still very satisfying.