Head Over Heels

Their first DA2 interaction when Guy makes the "That's a tall order," joke. He promptly notices that it doesn't land. Instead of pushing or doubling down, he apologizes and self-corrects.

When Guy is talking about his career to a group of servants and extras, he makes a beeline for Thomas the instant he's finished. He then asks Thomas about his experiences, compares Thomas favorably to himself (Thomas knows what he’s doing, Guy feels like he doesn’t), and his expression goes soft when Thomas offers a compliment in return. Guy sort of becomes the interested fan, and Thomas the star whose approval carries extra weight. 

Guy confesses his fears about his career falling apart, and places genuine weight on Thomas's reassurance.

After proposing in the pantry scene, Guy excuses himself, giving Thomas time and space to think about his offer; no insistence, no pressure. Wholly Thomas's choice. 

When Thomas asks Guy if the offer means what he thinks it does, Guy replies, “It can mean as much or as little as you like.” Again putting the ball in Thomas’s court.

He waits for Thomas to give Mary his notice, standing outside the room and looking nervous. It's only once Thomas smiles that he breaks into his own goofy grin.

Their first Grand Finale scene has Cora talking past Thomas (even calling him “Mr. Dexter’s dresser” to Noël, instead of using his name). When she asks Guy about returning to Downton, Thomas cuts in and says, “We’d like that very much, my lady.” He interrupts, inserts himself into the conversation, and answers for the pair of them—and Guy gets big heart eyes and touches him affectionately. He likes Thomas speaking on his behalf.

When Thomas tells Guy his place at Downton is in the kitchens, Guy doesn’t pause for even a moment to ask questions or try coaxing him upstairs. He follows immediately.

Before leaving the kitchens, Guy confirms that Thomas still intends to stay downstairs, and although it’s seemingly not the way they usually do things, he doesn't assume he knows better. He defers to Thomas's judgment.

I've already mentioned this, but the moment Guy asks Thomas upstairs! And seems bewildered at being asked, “Do you think I should?” The way his eyes dart back and forth like, “Does anyone else think this is weird?”

Followed by Guy pulling him aside before they join the party to ask if he's all right.

After Noël invites him to sing, Guy immediately looks to Thomas, and Thomas does the spouse-nudge to get Guy to join in.

Even at the fair, when Noël makes that ankles comment, it looks like Guy angles toward Thomas and leans closer to share their laughter as a pair. 

Anyway, I find it interesting that while their respective roles mean publicly, Thomas is in his shadow, privately Guy seems to orbit him like he’s his personal sun. When Thomas says, “I’m going downstairs,” Guy doesn’t say, “But you belong upstairs instead,” even if he's clearly confused; instead, he hurries to follow. Guy wants them on the same level, but he lets Thomas decide what that means.

There's this combination of admiration and basic respect, perhaps awareness that Thomas doesn't voice all of his needs without prompting... but also, YMMV, but it feels to me like a subversion of Thomas's life in service. A good servant is attuned to his master's needs, trying to foresee problems before they occur, following the master's lead, watching for gestures that indicate discomfort or displeasure.

But in their relationship, it's often Guy doing those things. Not in a subservient way (unless maybe they're into that, who knows), but because he cares. I think the moment where Guy adjusts Thomas's tie is a wonderful visual parallel to this, him performing an act that echoes Thomas's job as valet.