Saw Dr. Robert Ballard (who found the Titanic wreckage) give a keynote at Networld+Interop a few years ago - talking about dealing with change in your career. He had great examples of when he got his PhD, scientists 'knew' so many things about the ocean floor (static, lifeless). Then as they were able to explore it further, they found geothermal vents and all the creatures that lived there. Basically contradicting a lot of what they were taught in grad school.