I tested three standard deviations above the mean on the WAIS-IV at 145. I was pretty proud of this for a little while. I'm at a top 20 university and coasting to the top of my class in most of my math/EE courses. I still gotta work, but I work half as hard as most people who get Bs do, and still have a 3.9.
But 145 is one in a thousand, and there are three-hundred million people in the United States alone. 300,000 people that are smarter than me. They could fill a relatively large city with people, and I'd be the dumbest person there. There are so many fucking smart people out there, that even if you're a genetic fluke, it still feels like you don't stand a chance against the raw talent you're up against.