If I must narrow it down, I think I'll put in a mention of the Weyoun-Dukat scene in the Season 6 opening arc, where they're discussing Dukat's role as leader of the Occupation. The smirk on Weyoun's face as Dukat prattles on about how he "loved the Bajorans like my own children" is perfect. It's only topped by the way Combs delivers his answer to Dukat's question "But to this day, are there any statues of me on Bajor?": "I would guess not". Weyoun is playing along with Dukat's egotistical madness while simultaneously mocking it, and Dukat knows Weyoun is laughing at him, not with him, but is too self-involved to actually point it out. You really get the impression Weyoun knows this perfectly, that he has Dukat completly under control. He can be a jerk and mock him, because as long as he keeps it understated Dukat will never point it out or even admit it's there. Weyoun is playing with Dukat. He knows this man, knows how to handle him. Others here have posted about the masterful scene with Kira using Leeta to try and get Rom freed, and how well written and acted it is. they are right, and this interaction with Dukat is another such scene.