All of my characters' stories are closely linked with either power, tradition, or both. Machiavellian intriguers trying to acquire positions of authority, sons trying to become the men that their forefathers wanted them to be, etc.
Personal relationships—love and so on—are mostly boring to me, except as a portion of tradition, of what is expected of a person. In my writing, every action that every character takes is either a loss or acquisition of power, and an acceptance or refusal of tradition. The conflict and reconciliation between power and tradition is a recurring theme in most everything that I write.
It is worth noting that I mostly gravitate towards Nation RPs. They facilitate these sort of themes the best, I've found.