After reading the Sam Zell biography I notice when other entrepreneurs and podcasters take note. A podcast randomly popped up called "Founders" and he talks about his lunch with the 81 year old professional opportunist. Some of the great notes from the podcast is that you always need to be working for fun and not because you feel like its work. If it feels like its work then you are in trouble. Equally important is to optimize for freedom.
Another great quote from a recommended book from Zeckendorf a New York real estate work horse who was a big inspiration for a younge Zell. He says If you want to know whether you are destined to be a success or failure in life the test is whether or not you can save money you will lose money as sure as you will live if you can not save money.
Every single entrepreneur from history was known and what their company was according to the Founders podcaster and he mentioned a railroad magnate to read about named: James Jay Hill who was also a big inspiration for Charlie Munger.