Pretty much any Intimidate option in Mass Effect. You are one evil bastard, but it is just so fun.
Also being hatefully xenophobic while my teammates are aliens.
There are some great guilty pleasures in Galactic Civilizations II. Such as building up your military like crazy while remaining peaceful on the front, and then launching an all-out war against your weakest neighbor.
If you do it right they surrender their entire civilization to you, without any demands, after just one attack.
mixing various miracles in black and white 2 and testing them on my own villagers 😈
star wars BF 2
me and my friend slaughtering an entire guild in a jedi match (2 vs. all of them) during a tourny..good times..our guild rocked 😄
detpack throwing
mine thowing
watching my enemies burn (bothan incenterator ftw!!)
sneaking up on my enemies, knowing that very soon ill be watching them burn (bothan stealth ftdoublew!)
landing emperor palpatines midair attack....right into a large group of enemies