I am interested in how this core mechanic gets used in games. I tend to use it as a subtle instrument for Narrative reasons and as a Threshold for dealing with NPCs, but I don't make a big addition to the story in the session unless someone rolls doubles, and maybe not even then depending on the actual obligation. I am interested in hearing at what concentration of strength you use Obligation. For instance, if Obligation is triggered is that basically what the session will be about that night? Do you use it to represent financial loans quite a bit?
How much narrative power do you give it in the session?