Risk by definition is what is left over when you think you've thought of everything. An extreme adherence to an investing strategy is dangerous in a world that changes all the time. Benjamin Graham's great book, The Intelligent Investor, was updated four times before it became outdated and outmoded.
There are only a handful of financial rules, ideas, and observations that really move the needle -- and explain the majority of what you need to know to do better with your money.
I could have narrowed this down to 10, but I had fun with this thought experiment, so here are my top 30 rules of the money game.