Sentinel: *Sees a crashed Starscream* What is that thing?!
Optimus: Huh, that's right, you've never seen one up close. It's called a "Decepticon".
Megatron and Starscream's battle of wills continues in the Season 3 premiere "TransWarped", where Starscream gets so fed up that he starts ranting about how Megatron got them into this mess: "Are you seeing a pattern here? THIS! IS! ALL! YOUR! FAUUUULLLLTTTTT!"
The 2008 Botcon script reading "Bee in the City" is the funniest thing this troper has ever seen/heard, full of shout-outs and fourth wall breaks aplenty. Watchithere.
And earlier, Sari trying to teach Ratchet some manners:
Ratchet: Will you get in already!?
Sari: Ah, ah, ah, what's the magic word...
During the final confrontation with Wreck-Gar:
Ratchet: You glitch-head! You're gonna destroy the whole city! You wouldn't dare do something that stupid! Wreck-Gar: I am Wreck-Gar! I dare to be stupid! I will destroy the whole city! Ratchet: All right, you've forced me to make the ultimate sacrifice; to do the one thing that requires more courage than anything I've ever had to do in my entire Autobot career! I... apologize. Wreck-Gar: Come again?
The rivalry between Lugnut and Shockwave during "Endgame". Special mention goes to near the start of Part 1, when after some jibing from Starscream, Lugnut moves in front of Megatron punting Shockwave offscreen in the progess.
Starscream: Y'see, now [Megatron] even likes Blitzwing better than you. Hmm... *Shockwave meanwhile has walked back onscreen*
Lugnut: *Slaps Shockwave back offscreen* NO! I am the most faithful!