As you build things, whether they're train tracks, or bookshelves, or relationships, or essays that you've written for classes, the endowment effect … - Annie Duke

In large part, we are what we do, and our identity is closely connected with whatever we're focused on, including our careers, relationships, projects, and hobbies. When we quit any of those things, we have to deal with the prospect of quitting part of our identity. And that is painful.

We are much more bothered by the downside potential of changing course than we are by the downside potential of staying on the path we're already on.

Outcomes don't tell us what's our fault and what isn't, what we should take credit for and what we shouldn't. Unlike in chess, we can't simply work backward from the quality of the outcome to determine the quality of our beliefs or decisions. This makes learning from outcomes a pretty haphazard process.