Partly, this is because I was already familiar with a number of the behaviors that the author covered, and it sometimes had a "pointing out the obvious" quality. This was particularly evident when the author would spend a chapter laying out, say, the common belief fallacy (the tendency to think that if a lot of people believe something it is therefore true), and then giving advice like "so don't do that." And yes, being aware that you're inclined to ignore information that contradicts your beliefs and only remember what supports it is somewha helpful in remembering not to do it. But only somewhat.
I was (unfairly) hoping for more: for a way to get my irrational urges to fight each other and thereby cancel out, maybe. Or brain-hacking techniques that would let me put my quirks to constructive use. There's some stuff on that angle in "The Misattribution of Arousal", which is that humans can't really tell why their bodies are reacting a certain way or even what they're feeling. (The demonstrating experiment suggested that men can't tell the difference between 'I am shaky and sweating because this bridge is very high, swaying, and terrifying' and 'I am shaky and sweating because this woman is sexy'). And so the brain-hacking technique is "do scary/difficult things together to strengthen relationships, because you'll attribute the satisfaction of success to the other person." Which is cool! But there wasn't as much of that as I was hoping for.
A couple of things that more reasonably bothered me:
1) The book had an overly reverent attitude towards scientific findings. It gave the feeling of "here's an experiment, and here's the conclusions the experimenters drew, and those conclusions are therefore indisputably factual." Absolutely, the scientific method is the best tool we have for finding out stuff. But especially in psych experiments, there are a LOT of variables, and even if a study supports the given conclusions, that doesn't actually mean those conclusions are True. There could be other factors at work that the scientists didn't think to control for, or a competing explanation that also fits the facts.
2) Often, things were presented as "humans are like X" and the example of a study that supported X would involve a bunch of college-age Americans. I kept wondering how much of this stuff was 'universal' and how much as particular to the culture of the scientists conducting the experiment. I mean, maybe these studies were repeated across all cultures/genders/ages/etc. and the book was just mentioning this particular study as an example because (narrative bias!) people pay more attention to stories than to disconnected facts. But I still wished the author had made a clearer distinction between "this is one 50-person study that supports a nifty hypothesis" and "this is a study that has been reproduced thousands of times across the globe with similar results".
So it had a very "popular science" feel to it. The author didn't footnote his sources in scholarly style, but there is a long list of the sources by chapter at the end, so it's by no means devoid of citation
Still, there was some good stuff that I hadn't heard before, or hadn't heard in this way. Like "enclothed cognition" (dressing the part actually makes the brain better at doing it) and "the overjustification effect" (the brain's tendency to attribute feelings to external reasons if any are available, and to only make up internal reasons if they aren't).
"Ego depletion" was one of the interesting ones, because it postulated that there's a finite supply of whatever it is that humans use to make decisions, apparently connected to willpower. This gets used up when you're trying to restrain impulses (like not eating cookies), or deal with rejection, or make decisions. Do a lot of one thing, and it's harder to do the others later. That test subjects would go with bad defaults -- listening to something boring for longer because they didn't have the mental energy left to press a button and stop it -- was particularly interesting to me. So it seemed not to be using up the ability to tolerate crap, so much as using up the ability to make changes.
But overall, I enjoyed reading it, and may pick up the author's previous work some time. It does make me more aware of patterns in my thinking, which is fun in its own way. I'll give it an 8.