Maybe I only think that because I had an ex who was rather like GLaDOS: "If you won't stay with me, I'll manipulate you until you will", "If you won't be manipulated, I'll do hideous things to both of us", "I don't need you, I never needed you, I only stuck around because you needed me to", "I am so incredibly over you that you wouldn't believe it — let me tell you in great detail", and so on.
GLaDOS is both more approachable and scarier than SHODAN, High Queen Bitch of female AIs. After all, SHODAN is the archetypal ice queen. She's not human, she's well out of your league and makes sure that you know it, and it's actually rather scary that she's focusing her attention on you. GLaDOS is the girl you meet in a club, she's smart but shy about it, you bring her out of herself, have some fun, and then before you know it and almost without realising it, you're in a highly dysfunctional relationship that's going to blow up messily at some point in the near future. She's not definitely scary until it's already too late. At least with SHODAN you know what you're getting.
: gominokouhai went to high school with one member of Scarlet, I went to high school with the other. They were a couple of years our senior, but even so.
: Which of course ties in with XERXES in System Shock 2. XERXES is just as intelligent as SHODAN, but he doesn't give a fuck about humans at all. He doesn't interact with them in any ways above the entirely impersonal because of SHODAN — going back to the metaphor, she's the posh dominatrix who started shagging the gardner's boy but makes sure that he knows she's always in control, while he's the traditional toff who doesn't interact with his staff beyond a purely functional level.