The first twenty that come to mind [with a few edited out as having already been mentioned]:
1. Shadow. Every minute.
2. Killer. Every minute.
3. Gambit: Jarriere's reaction shots. Travis's hat deserves a mention, too.
4. Bounty: Blake threatening to destroy Sarkoff's butterflies.
5. Bounty: VILA: Avon? AVON: What? VILA: Shut up. Please. [Avon turns away and smiles.]
6. Deliverance: BLAKE: How did it feel? AVON: Don't you know? BLAKE: Yes. I don't like the responsibility, either. [Avon rises, looks at Blake, then leaves the flight deck.]
7. City: VILA: All right then, give me a good reason. I'm a reasonable man. I'll accept a good reason. I'll accept a bad reason. I'll accept any damn reason at all, just tell me what the hell it is I'm meant to have done.
8. Trial: Every minute Brian Croucher is on the screen.
9. Trial: "Avon's gadget works!" - and Avon's reaction to same.
10. Volcano: Avon and Vila commiserating on the flight deck.
11. Rumors: Tarrant demoting Avon to "Section Leader".
12. Redemption: "So long as you're not standing behind me." - and Avon's reaction to same.
13. Gambit: Avon and Vila put one over on Orac.
14. Orbit: "Vila weighs seventy-three kilos, Avon."
15. Gold: Vila confronting Keillor.
16. Star One: The "wade in blood" speech, capped off by "You really do hate me, don't you?" - and Avon's reaction to same.
17. Traitor: "I need to kill her myself."
18. Mission to Destiny: Avon getting turned around by the sleep gas.
19. Pressure Point: Kasabi's dead-on assessment of Servalan.
20. Any episode: When the opening credits begin and I hear the cheesy theme song and instantly feel about three notches happier.
Mistral