Thanks to decades of research in human behaviour, we know we are systematically biased in manners that are often quite predictable. In Nudge: Improving Decisions About Health, Wealth, and Happiness, the authors apply these learnings to real-life situations in order to improve outcomes.
None of the biases discussed are new, but I don't think that's a bad thing. I've read enough books on behaviour to recognize all of them, but because I don't re-read most of these books, getting reminded in the books I haven't read before is helpful.
The application of these biases towards improving outcomes in real life is pretty awesome. For example, people just don't care enough about most things to change the default option, no matter what it is. So one easy way to improve outcomes is to change the default. E.g. Instead of having people opt-in as organ donors, have them opt-out if they so choose; this simple change has saved thousands of lives in other countries.
I highly recommend the book to anyone who finds this topic interesting.