I've read all of Jeff Bezos's 23 years of Amazon shareholder letters twice now.

It's an MBA of its own.

Here's what I learned about startups, entrepreneurship, investing and more:

Your customers are loyal to you right up until the second that someone else offers them a better service.

Listen to customers, but don't just listen
to customers also invent on their behalf.

Here's Jeff Bezos on coming up with the Amazon Kindle:

We set ourselves the incredibly audacious goal of improving upon the physical book.

So don't be afraid to set big goals.

And remember that if you don't execute well, it will be done by someone else.

Many of the problems you'll face will have no textbook solutions, and so you should happily invent new approaches.