I finished reading Project Hail Mary today and I've been crying on and off about Ryland goddamn Grace only finding true companionship in an alien species, in the middle of a foreign solar system, struggling to fight for the survival of his planet.
In all of the flashbacks we see, he struggles to connect with the people around him. He was ostracized by the scientific community for his controversial paper. He had such strong imposter syndrome that he felt isolated from the other workers on the PHM team, both the mechanics and scientists, as well as the astronauts and think tank/project managers. He finds solace in the army guards by the doors of his miscellaneous labs, but he doesn't know them-- he almost anthropomorphises them. He teaches the astronauts planning on sacrificing their lives everything he knows about molecular biology, but they aren't 'friends', per se. We don't get a clear answer on the age difference between the different characters, but the astronauts seem to treat Grace like a superior, with respect but distance as well.
Whereas Rocky?
He is IMMEDIATELY perceived as a friend. Before Grace even knew that there was intelligent alien life on the ship across from him in Tau Ceti orbit, he felt that Rocky's ship mimicking his ship's movements was friendly and inviting. They wave at each other excitedly, geeking out at the other's methods of measurement, of time. They get a working language going, and fall into science head-first. However, as the months go on, their communication expands to include jokes and sarcasm, cultural exchanges of intimate importance, and stories of their personal lives. They respect and trust each other, but still make time to tell jokes and make the other laugh.
On Earth, Grace felt like an outsider with very little pertinent knowledge. In Tau Ceti's orbit, though, he is both student and teacher! He gets to both teach an enraptured audience, as well as learn uniquely challenging new processes. He never seems to feel belittled by Rocky's knowledge, only proud and impressed. Grace works hard to be an academic equal to Rocky, not due to imposter syndrome, but instead to further Rocky's ideas and challenge them into new directions. Grace and Rocky are collaborators, truly working together to solve the astrophage problem. During the flashbacks of Earth, Grace acts as sort of a passive observer of the events unfolding. On the Hail Mary, he and Rocky are firmly in control.
It took thirteen light-years for Ryland Grace to feel seen.
It took a handful of months to understand the importance of that, and probably less than an hour to decide that that feeling was more important than any celebrations on Earth could be.