The most important concepts author highlited at the end of the book are:

• Go out of your way to find humility when things are going right and forgiveness/compassion when they go wrong.

• Less ego, more wealth - save money.

• Manage your money in a way that helps you sleep at night.

• If you want to do better as an investor, the single most powerful thing you can do is increase your time horizon.

• Become OK with a lot of things going wrong. You can be wrong half the time and still make a fortune.

• Use money to gain control over your time.

• Be nicer and less flashy.

• Save. Just save. You don't need a specific reason to save.

• Define the cost of success and be ready to pay it.

• Worship room for error.

• Avoid the extreme ends of financial decisions. The more extreme decisions are, the more you may regret them as you evolve.

• You should like risk because it pays off over time.

• Define the game you're playing, and make sure your actions are not being influenced by people playing a different game.

• Respect the mess.

In understood the book in this way:

• No one is crazy.

• It's never as good or bad as it looks.

• Luck plays a big role in our lives.

• Always think about probabilities in decisions involving humans, due to emotions, instability, and greed.

• From my experience as a software engineer: when dealing with people, think in probabilities, not precise units. When estimating software projects, consider irrational human behavior to provide more accurate estimates.

• Always save money for the future.

• Leave room for error, protected by saved money.

• Always have flexibility in career or any decision. Saved money provides this flexibility.

• Life decisions can't be perfect; I use SWOT analysis to make better decisions. While not in this book, SWOT analysis complements its concepts well.

• Everything has its price.

• Everyone has their own thoughts about any decision you make, and that's okay. We naturally form opinions.

• Humans often fill knowledge gaps with assumptions; it doesn't make them stupid.

• People tend to prefer pessimism over optimism.

• When you believe in something, you see signals that confirm your beliefs.

• Think about odds in your decisions.

• Expensive cars and houses don't indicate wealth; they might suggest large debts.

• Wealth is the ability to manage your time as you wish.

• No one is as impressed with your possessions as you are.

• Everyon's life is a continuous chain of surprises.

The Psychology of Money is a good book that explores psychological aspects of human behavior and money. I recommend it, but it wasn't groundbreaking for me—just a good read.