I'll be turn this argument on it's head now I'm afraid:
I, as the person playing the game, have never yet been angry at another player, or spiteful, or anything along those lines. Possibly I might admire his tactics that led him to be able to beat me, and if the interaction with him (on the forums, by PM, or otherwise) was fun I (still as the person) might hope he goes on to win the game.
I, as the player (as opposed to the person playing the game described above) will - obviously - do anything I can think of that will allow me to beat my opponent. But, if/when that happens to fail I actually see it not only as justified, but actually as my
duty to the game and all the other players to try and hurt my opponent(s) as badly as possible, by any means I can think of. Mostly this resolves about using my troops to directly do as much damage as they can before they die, and try to gain as much time as possible. I can't remember ever going so far as to pillage my own provinces for that purpose (usually, by the time I'm actually ready to throw the towell, all troops I've got left are besieged inside a fortress, as part of one of the doing damage/gaining time tactics) without the possibility to pillage
), but I definitely won't rule out doing it in the future.