I love the title "test pilot". The fucking rodeo clowns of the aeronautical world. Your sole job is to make sure the rest of the world survives riding this jet long after you have worked the bugs out of it at 2000 mph.
Similar, but not quite as intense, is when you find that bitchin front end somewhere in a barn, swap meet (hint) or along one of the isles of the Internet. The reality of the risk of your decision comes full circle on that first ride when you can fully envision that thing disintegrating in front of you as you blast down the road.