I can easily rationalise Picards behaviour in Nemesis with a few things. Picard was probably disillusioned with Starfleet at this point especially after INS and his relegation to the sidelines at the start of FC instead of leading fleet. Picards whole phikosophy of 24th century enlightenment was slowly being destroyed by the events he witness such as the emergence of the Maqui and the Dominion War. He no longer has hope of holding onto these notions of a Utopian Society because that "everlasting peace" didn't last nearly as long as he had wished for and tried to preserve for his entire career. In NEM we see an aging captain who probably doesn't see much value in his chair, especially compared with how he was at the start of TNG - brimming with passion and patriotic spirit for the 'Utopia' that was the UFP. All his work and sacrifice for what? Simply for everything he has worked for to fall apart around him and the Federation revert a century's worth of progress and fall into moral corruption as seen on DS9. NEMs Picard is frankly sick of everyone's BS and happy to retire but chooses not to because being in Starfleet is all he's ever known. And still this version of Picard still manages to import some wisdom on Data in a heartwarming scene but that was cut from the film! He still manages to save the day albeit with data's sacrifice. After all Picard has been through: being assimilated, sorted 1000 different diplomatic and political issues, discovered 500 new alien life forms, being constantly manipulated by Q, time travelling to save the entire human race, and everything else... You would think he deserves a scene where he receives a medal or some kind of external recognition. He sacrificed family, being a parent and put all he was into Starfleet. I love Picard because he keeps going no matter what. And now finally Season 3 of Picard has reminded me why I love the character. Because he may have retired but he never gives up! He saved the world again as a nonogenarian and prioritises his son to a degree no one expected. The same authority and confidence came out to prove to everyone that the old Badass Picard was still there the entire time! Now he can finally retire to Risa and catalogue old alien artifacts in peace.