I’ve had brakes fail twice. Both times they didn’t fail completely.
The first time was many years ago when I was in college. I was driving a 1978 Olds Delta 88 (a big-ass hunk of American steel) and going down hill. There was a teeny-tiny little foreign car in front of me, and the brakes chose that moment to fail. I was certain that I was going to knock that tiny car right out onto the main road. My car managed to stop a few inches short of smashing into the little car, and I don’t think the driver of that car realized how close they had come to getting creamed.
The second time I was driving my Cadillac home from work and the pedal went to the floor. Fortunately I was in a residential neighborhood that I cut through on the way home that has a 25 mph speed limit, and I still had some brakes, so no biggie. I managed to limp the car home, which is about a 45 minute drive, but very few stops along the way. I just gave myself a lot of room between me and the car in front of me.
ETA: Not brakes, but I once had the throttle stick while driving up 270 coming up from the DC beltway. When I pushed in the clutch pedal in the engine revved very high, so I let the clutch out so that I wouldn’t destroy the engine. Once I managed to get over into the right lane I pushed the clutch in, shut the engine off, and coasted to a stop on the side of the road.