Every leader is assigned one historical agenda based on something they did while ruling their nation in actual history, Beach explains. Lets take a leader who built a whole bunch of wonders. In our universe, that leader is going to feel like hes better than anyone else in world history at building wonders, and that should be reflected every time they are in a Civilization game. Wonder obsessed. So that civilization will get a bonus toward building wonders, but they also get an obsessive personality where he will get angry if anyone else is building more wonders than they are. So you might have a strategy where you always go for Stonehenge and Hanging Gardens so you grab those right away. If this guy is next to you and he sees you doing this, hes going to be up in arms and invading your borders."
Leaders will also have a hidden agenda that will be assigned to them that will change from game to game, so even if you know the opposing leader's core personality, you have to discover additional, dynamic traits if you want your political agendas to progress smoothly.