About contract leverage;
Buffett once told a story: There are 100 bullet holes in a pistol, and 1 bullet is loaded. If you shoot yourself in the head, you will be given 1 million US dollars. Will you do it? Most people who hesitate to do it will not have a good life result because of greed!
Another sentence that Buffett said is also very profound: Don't risk losing what you need and have to get what you don't need!