Wheatley

Wheatley was a charming edition to Portal 2, actually having a companion to guide you through aperture science. When he betrays you after having access to the mainframe, it doesn't take a genius to predict he would, Absolute power corrupts absolutely and based on how you failed to catch him when he asked you to, it would make sense for him to take his anger out on you, especially Glados for calling him a robot DESIGNED to be an absolute idiot. Meanwhile, Glados from the first game was written to have NO redeeming qualities. Her reward for completing the tests is throwing you into a fire pit to die. And her backstory is revealed that she POISONED the entire aperture staff with neurotoxin. It was a bit of a bold decision to give her a backstory in the 2nd game, to try to give her sympathetic qualities. I just wish it didn't end with Wheatley being banished to space like that, nobody deserves that kind of fate. I wish there was a way to save him. :(