Cake, and grief counselling, will be available at the conclusion of the test.
I know she's (it?) been mentioned before but I think GlaDOS should be on this list. Not only is she utterly ruthless but also is only doing what she's been programmed to...
"There was even going to be a party for you. A big party that all your friends were invited to. I invited your best friend, the Companion Cube. Of course, he couldn't come because you murdered him. All your other friends couldn't come, either, because you don't have any other friends because of how unlikable you are. It says so right here in your personnel file: "Unlikable. Liked by no one. A bitter, unlikable loner, whose passing shall not be mourned. Shall NOT be mourned." That's exactly what it says. Very formal. Very official. It also says you were adopted, so that's funny, too. "
"You look ugly in that jumpsuit. That's not my opinion; it's right here on your fact sheet. They said on everyone else it looked fine, but on you, it looked hideous. But still what does an old engineer know about fashion? Oh, wait, it's a she. Still, what does she know about - oh, wait. She has a medical degree. In fashion. From France."