Dinosaurs may have been the most successful creatures ever to colonize the earth.With our 100-year-max life spans, human beings aren't well adapted to understanding “deep time,” as geologists call it.
Modern humans have only existed for a few hundred thousand years, and human civilization only got going about 10,000 years ago, mere blinks of the eye by Jurassic time scales. Everyone talks about how dramatically (and irrevocably) they went extinct, but judging by the immense amount of time they lasted.