Hm. I always play my first game good, because I have a natural tendency to want to be nice to people. Except for people like the Quarren Exchange goons. I just wanna rub those geeks out. But being evil has its kicks. Three of them, to be exact. One was Force persuading Zaalbar to be your slave and to kill Mission. That was a powertrip and a half. Then force persuading the goons on Nar Shadaa to give you their money and then throw themselves off of the ledge. And lastly, the most insidious, evil, twisted and enjoyable moment was converting Atton to become a Sith padawan. Oh man, was that fun.
Why? He hated him his entire life then left his life because he hated them and loved them at the same time. He never liked the Jedi, making him hate the Jedi seems natural for me, he just needs a little persuasion. The same goes for Jedi... I actually believe you are hurting Atton more if you are making him a Jedi then if you are making him a Sith