Picard seems to regard Shinzon like a long-lost relative at first. He's hesitant to trust him (and turns out he was right to do so), but when they finally talk, they realize how much they truly have in common. "The Remans gave me my future. You can give me my past."
Shinzon: Were we Picards always warriors?
Picard:' I think of myself as an explorer.
Shinzon: Well, were we always explorers?
Picard: I was the first Picard to leave our solar system. It caused quite a stir in the family. But I'd spent my youth...
Shinzon: ...Looking up at the stars, dreaming about what was up there...about...
Picard:' ...New worlds...
Picard and Beverly reminiscing over his old Academy photos.
The novelization of the film features a very bittersweet moment of heartwarming when Data dies. Just before he destroys the Thalaron Matrix, Data accesses every single memory he has of his friends on the Enterprise, and experiences them all as he's vaporized.
"You've earned a friend in the Romulan Empire. The first of many, I hope."
Picard welcomes medical assistance from the Romulans.
Picard: Geordi, ...prepare the shuttlebay for arrivals. They... They don't know our procedures. ...Just open the doors.
Worf, of all people, saying that "The Romulans... fought with honor."note His tone says, "These guys don't."
I always saw that more as the Fantastic Racism between Klingons and Romulans coming out. His family was killed by Romulans, and he spent a good chunk of his life in dishonor for it. Klingons in general view the Romulans as devious tricksters and not true warriors. Worf had just witnessed two warbirds charge headfirst into battle, not even bothering to use their cloaking devices... and noticed that even a Romulan can be an honorable warrior.
Picard and Riker's final scene together:
Riker: Serving with you has been an honor. Picard: The honor was mine... Captain.
Patrick Stewart burst into tears filming this scene. True Companions, indeed.
Data manages to convey this to Geordi without saying a word before jumping onto 'Scimitar.
The entire wedding ceremony is one big CMOH
Whether you go by the cut scenes that have him say he's joining the Titan's engineering crew or the novels idea that he is still a Traveler (and just wearing a Starfleet uniform because he expected to be arriving at a wedding in the Betazoid fashionnote meaning nude, Wesley's appearance is this on its own, as the last time we saw him, he was leaving his family and going off to greater things, but he came back to be there for Riker and Troi's wedding.
This exchange between Picard and Commander Donatra, showing once more that there is hope for the Federation and the Romulans working together.
Picard: Commander, when this is over I owe you a drink.
Very subtle, but after Donatra offers them assistance, she states "The Empire considers this a matter of internal security. We regret you've become involved." as the reason. The last time Picard heard that line onscreen, it was from a seemingly-benign government cutting off discussion about treatment of their solders, leading him to note "'A matter of internal security.' The age-old cry of the oppressor." This time however, it has the opposite context; the legitimate government is fighting against the true oppressor.
Janeway's cameo. Even if you've already seen the Voyager finale, it's still so great to hear a cordial Picard calling her Admiral Janeway. Provided you don't find it gut-bustingly hilarious thanks to the now extremely prevalent theory she was Kicked Upstairs.
The cordial way he greets her, too, suggesting that the two have met in casual settings and get along - in comparison to Sisko's understandable icy reception towards Picard (even acknowledging the thaw at the end of Emissary), the implied friendship is just nice to see, a reminder that as big as Starfleet is as an organization, there is this camaraderie between captains (or former captains).
And, really, one can't ignore the fact that, for those who love Star Trek: Voyager, seeing the captain of Star Trek: The Next Generation - the series that Voyager often seemed to exist in the shadow of trying to meet - greet her warmly is a nice moment that says that yes, Voyager is a welcome and accepted part of the Star Trek family.
A deleted scene from the end of the film has Geordi and Worf cleaning out Data's quarters, packing up his many mementos of his time with the crew (far more than he had when he was packing up in "The Measure of a Man"). Suddenly Spot appears and leaps into Worf's arms.
