Cal Callahan is a friend who had a long and successful career as a financial trader. But at a certain point, he wasn't happy and didn't feel authentic in his role. He did what few successful people really know how to do: get out while he's ahead. Cal has a humble perspective on life, which is refreshing and rare for someone in their mid-40's. A reflection of that is The Great Unlearn podcast that he hosts. If you feel "stuck" in a career position, I highly recommend checking out his wisdom.