People are almost infinitely adaptable for short time periods.
However, they are also capable of making errors of every imaginable type, and have specific limitations on vision, hearing, grip, strength, dexterity, and attention span. Ergonomics handbooks contain data on various population segments, showing the range of size, strength, and motion range. While many engineering students realize the need to consider physical human factors in design few realize the importance of the psychological factors in designs that contribute to the way people use equipment. It is unreasonable to expect human beings to act perfectly, to always obey all the rules, regulations, and instructions. This, however, is exactly the philosophy of some equipment manufacturers, and of some employers.