An egregious example of bad evolutionary "design" is the recurrent laryngeal nerve, which is a bad-enough mistake in humans, but reaches comical proportions in giraffes. As all tetrapod vertebrates have a similar arrangement, it would have been even more comical in the longer-necked sauropod dinosaurs. The nerve would have been as long as 28m (92 ft) in Supersaurus, almost all of which was an unnecessary detour.
Other popular books on evolution mention this remarkably bad design, including: Why Evolution Is True (2009) by Jerry Coyne; The Greatest Show on Earth: The Evidence for Evolution (2009) by Richard Dawkins; and Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body (2008) by Neil Shubin.
But I'll focus on whales today, specifically their superhuman resistance to choking and cancer, two serious killers of humans.