I wish I could get GLaDOS's voice as a replacement for Siri's, and she'd just be a total bitch about everything. So even if she couldn't figure out what I wanted or whatever, she would just come back with something like, "I could tell you that, but I really don't feel like telling you, I would rather you suffered for the rest of the day, not knowing the answer." Just make her non-answers something I actually wanted to hear her say.
Spoilers below (and apologies, as I can’t get the spoiler tag to work. If someone knows, let me know!).
In Portal 2, you learn the GLaDOS is actually the brain dump of Cave Johnson’s assistant, named Caroline. Cave Johnson is the one that ran the company that created the portal gun.
Because she's the mind of Cave Johnson's assistant Caroline copied into the computer. GLaDOS is actually an anagram acronym of "Genetic Lifeform and Disk Operating System"