Stephen Hawking traps Robo on a year long flight to Mars, with nothing to do or read, and Robo doesn't have a sleep mode. He retaliates by arranging countless martian rocks to proclaim 'Hawking is a bastard' in letters big enough to be seen from space.
Atomic Robo and Dr. Dinosaur squabble over grammar:
Dr. Dinosaur: That is for me to know and for you to die!
Robo: That's not even a sentence.
Dr. Dinosaur: The simple mammalian subject and predicate were both represented! I challenge your claim.
Also in the companion story Why Atomic Robo Hates Dr.Dinosaur, Dr. Dinosaur surrendered to Atomic Robo and gave him his crystals he was going to use for time travel... which was actually a cooler full of grenades that Dr. Dinosaur took the pins from. The silent look of pure hate on Robo'S face and the look of smug superiority on Dr. Dinosaur is hilarious.
Dr. Dinosaur: I knew you would be here, Atomic Hobo! Witness how I have deconstructed your name into an insult.
Let's just say: everything involving Dr. Dinosaur.
Another couple brilliant ones from the 2011 Free Comic Book Day story:
Dr. Dinosaur:Shut up! I hacked your mainframe and downloaded your itinerary. Yes! All of your computerized scheduling secrets are now mine!
Atomic Robo: You joined our newsletter!
Dr. Dinosaur:You can't prove that!
After Robo questions how Dr. Dinosaur got guns it flashes back to...
One Week Ago...
Alonso (of "Alonso's Gun Hut"): 'Fraid I'm going to have to see some I.D.
Best of all. Dr dinosaur is one of the few "Villains" that keep outsmarting Robo and his team (several times including Jenkins) in every encounter, leaving the Team either stranded or beaten. It infuriates and shames Robo to no end.
In volume #3 of The Shadow from Beyond, after Atomic Robo managed to cage the beast and is waiting until morning, Robo goes to read a book of Temporal Mechanics... until four panels later where he switches to a Conan The barbarian comic. Made funnier because he is complaining about a wizard, a species that he professed to detest.
Much to the exasperation of his future selves, 1926!Robo has a bit of trouble getting to grips with the idea that the same event is happening only once, but from different perspectives:
1926!Robo: What if we do something we didn't do before? 1957!Robo: It's not like that. This is only happening once, we're just witnessing it from different points in our life. 1926!Robo: Banana oil. 2009!Robo: Yeah, that's the third time I've heard you say that, not counting the time I was you when I said it, and every time I say this: shut up and listen, the adults are talking.
In the first volume, we get this gem:
Tesladyne Scientist: Robo, there's a pyramid in Egypt!
Robo: Yes, thank you, that's super.
From the same story we get this:
Robo: I didn't start this company all those years ago to not nuke things!
Action Scientist: They didn't even have nukes when you started this company.
Robo: Yes, but shut up.
At the end of it:
Robo: You're exhausted, I can read your brainwaves with my special robot eyes.
Action Scientist: Really?
Robo: Of course not. the fact that you even believed that proves how tired you are!
During Robo's first fight against the Eldritch Abomination, he gets a call from Tesla and has to pretend that the fighting noises are just from a radio show he's listening to. Hilarity Ensues.
Robo starts to fight against "Futuresaurus Rex", which instantly deploys rocket launchers, cannons, machine guns and the like only to then SPIT OUT two Mauser Pistols and take them in its tiny hands. Robo says it best: