His attitude towards children markedly changes.
As recently as the episode Disaster (s5e05), Picard expresses visible discomfort about vamping for a few hours with young children. After making a new life for himself and raising children with his wife in The Inner Light (s5e25) there isn't a whole lot of interaction between Picard and children (not counting Rascals, sigh) -- but in the movie Star Trek: Generations, we find that his first, ideal imaginary paradise is Thanksgiving dinner, surrounded by children (his own, as well as recently departed Rene) and family.
If one were to roll tape back to 1st and 2nd season Picard, one would surmise that naught but Earl Grey tea and archeology books await him in the Nexus. There have been few other potential catalysts for this change besides his experience with the Ressikan probe.