I'm buying a house! A very exciting thing for me. In the process of finding and buying this house, I've come to some interesting game-theoretical realizations.

Observe the three-step process:

1. We find a house that we like.
2. We contact the agency to organize things between us, the bank, and the homeowners.
3. We do everything on our own, with the help of the homeowners.

Putanumonit Jacob has some great insights into how frequently you'd expect to see people not behave according to their incentives (trolls), and it's something like 4% of cases. I guess that's true in my experience. My added data point is that people follow their incentives but not reliably - or at least not reliably enough for me. The classification of people into incentive-followers (non-trolls) and incentive-ignorers (trolls) can be useful, but this experience acquainted me with mixed trolls. Sometimes they'd follow incentives, on other days, not so much. That's because they're playing other games as well, so they have to balance out the payout for my game with their other payouts.

That is to say, I cannot reliably count on the agent to do the things I need done (on time), even though him doing these things means that he gets paid 1% of the selling price. He also gets 1% on like twenty other transactions, which are maybe much more lucrative. Not all one percents are equal.

The unexpected side-effect of this story is making friends in unexpected places. The previous homeowners and us, we share a bond of interest in the house and a common dislike for the agent and the bank. It's circumstance that forces us to go through these proxies, instead of trading directly.

And the expected lesson is that when you have people do the work for you, you still have to do work. It's an instance of the principal-agent problem. No amount of money will allow you to outsource things perfectly. So it makes sense to try to do things on your own, learn the skills in the process, and pay for repairs if you mess things up too badly.