Superman: A game has rules. Your stunts are just random idiocy.
Mxyzptlk: Okay, I'll give you a rule. You make me say, spell or otherwise reveal my name backwards, and I'll split until our dimensions come into alignment again in about, oh, three months, say give or take.
Superman: I can't even say your name forward. How am I supposed to say it backward?
Mxyzptlk: No, dope! You don't have to say it backward. You have to get ME to say it.
Superman: Say what?
Mxyzptlk: Kltpzyxm! Gosh, you're thick! Now, for the last time - ah, nuts. [Disappears.].
Chris Potter: Shiny cow. Shiny cow. Mooo.
The Aptitude Test / Oskar Gets a Job - S3-E9
Arnold: Look, you wanted me to help you get a job, and I did.
Oskar: Yeah, you did. Good for you. [To Grandma] I'll be right back, my beautiful Fatima!
Arnold: Your first day on the job, you said you had the stomach flu, and today, you said you had a bad back.
Oskar: What's your point?
Arnold: My point is, are you going to have another excuse tomorrow, or are you going to do your own job instead of making me do it for you?
Oskar: Arnold, of course I'm going to do my job, don't worry.
Arnold: Good.
Oskar: But I can't tomorrow, it's a national holiday from my old country, I forgot to tell you.
Arnold: That's it! I'm tired of all your excuses!
Oskar: Arnold, you seem a little cranky, maybe you should take a nap.
Arnold: Look, I only helped you because you said you were desperate. You said you wanted to change. I guess I was wrong. Mr. Kokoshka, I'm sorry, but you are a huge loser!