Elon Musk breaks down the brutal math of high performance in this clip. While many look for shortcuts, he argues that the difference between success and failure often comes down to pure volume of effort. He advises that you must be “extremely tenacious” and “work like hell”—specifically citing 80 to 100-hour weeks. His logic is undeniable: If other people are putting in 40 hour work weeks and you’re putting in a hundred hour work weeks, then even if you’re doing the same thing you will achieve in 4 months what it takes them a year to achieve. Elon Musk identifies the single most difficult challenge for entrepreneurs: distinguishing between “believing” in your ideals and pursuing some unrealistic dream. He warns that the “natural human tendency is wishful thinking.” To succeed, you have to fight that instinct. You need to be focused on something that you are confident will have high value to others, but you must be “very rigorous in your self-analysis” to ensure it actually has merit.