The professor holds up a glass of water in class and asks students to guess its weight. After various guesses, he asks what would happen if he held it up for longer periods of time - minutes, hours, days. While the weight does not change, his arm would become sore, numb, and stressed. He then asks what he should do to relieve the pain, to which a student replies "put the glass down." The professor explains that problems in life are like holding the glass - they cause stress and paralysis if dwelled on for too long. It is important to 'put the problems down' at the end of each day to wake up fresh and able to handle challenges again the next day.