Avoid unnecessary transactional taxes and frictional costs; never take action for its own sake. - Charlie Munger

You don’t have a lot of envy, you don’t have a lot of resentment. You don’t overspend your income, you stay cheerful in spite of your troubles, you deal with reliable people, and you do what you’re supposed to do. And all these simple rules work so well to make your life better. And they’re so trite.

Obviously, you have to know accounting. It's the language of practical business life. It was a very useful thing to deliver to civilization. I've heard it came to civilization through Venice which of course was once the great commercial power in the Mediterranean. However, double-entry bookkeeping was a hell of an invention.
And it's not that hard to understand.
But you have to know enough about it to understand its limitations — because although accounting is the starting place, it's only a crude approximation. And it's not very hard to understand its limitations. For example, everyone can see that you have to more or less just guess at the useful life of a jet airplane or anything like that. Just because you express the depreciation rate in neat numbers doesn't make it anything you really know.

An example of a really responsible system is the system the Romans used when they built an arch. The guy who created the arch stood under it as the scaffolding was removed. It’s like packing your own parachute.