Narrow minds devoid of imagination. Intolerance, theories cut off from reality, empty terminology, usurped ideals, inflexible systems. Those are the things that really frighten me. What I absolutely fear and loathe.
It is important to learn to be surprised by simple things - for example, by the fact that bodies fall down, not up, and that they fall at a certain rate; that if pushed, they move on a flat surface in a straight line, not a circle; and so on. The beginning of science is the recognition that the simplest phenomena of life raise quite serious problems: Why are they as they are, instead of some different way?