Originally Posted by The Walkin' Dude
"Instead, I got to be myself for a change. I got to play a game how I wanted to play it, instead of how I thought I should be. If someone struck me as evil, I killed them and didn't worry about the extra quest they might have offered later. If the guards caught me, I killed them too."
The beauty here with Dishonored is that it's too easy to become "evil". If you want to sneak past the guards who, after all, are just trying to get through the day, you have to work for it. The evil playthrough, I find, is easier and, because it is so fun, very tempting.