Brilliant response. I've linked you a short article about the heuristics in the previous response. It's usually applied to software outside of games, but it's a great short few commandments to go by when it comes to usability. Just give it a read, and remember it when you design interactions.
As for the smug humour, I may have come across as meaning to say that your game does it constantly. That's not the case. It's somewhat present. And I believe I mentioned that your character (the AI that is), grows over time. In the simplest of terms, the issue is this. Permanently sarcastic characters are very popular nowadays. I'm not sure why. They are frequently irritating. This tends to lead to a cast made primarily of smart-arses. This happens in films, sit coms, and games as well, by osmosis. I'm not a guy that digs narratives very much in general, so take this feedback with a pinch of salt, but, whenever I write characters, I like to give them distinct personality traits. I then observe if the traits are matched as I write their lines. Sarcasm is a very cheap and easy to reach form of comedy. I suspect this is why it's as popular as it is. Having every character sound the same is the issue. Now, in the environment of your game's this cannot happen. You only have one character. But every time your character behaves like Glados would, it's very in your face. Glados is in fact a great example of a character that the world loves, and I find rather irritating. Another excellent example of this phenomenon is the whole cast in Borderlands 2 (2 specifically).
I can bang on about this for a while, but I suspect you understand exactly what I mean. So... :)
Viewing post in Differentiation game jam comments
Yeah I know what you mean. It was never a form of humor I found irritating but I see what you're getting at and I definitely agree with you. I dont make all my characters sarcastic but when it comes to narrator like entities (like L-13), I do tend to steer towards that direction which isnt best. And of course, considering the idea for this game was greatly inspired from portal, it is true that I copy Glados' behavior here and there. Im working on a bigger game where there'll be a lot lot more characters so that problem won't show up but yeah, I get you.