The higher the stress, the more valuable the object becomes.

Education: from K-12 to college ,  children are stressed out daily and trained  to cope with stress. The exams are set to stress students, and the scores are the results of stress handling.

Diamond:  the diamond is created out of thousands of tons of PSI force.

Physical competition: In all sports, its the ability to handle stress that sets you apart from other players. The stress of the clutch shot, either the shot is stressful for you or its just another shot.

Army: the higher amount of stress you can handle in basic training, the higher amount of resistance you can provide on the battlefield.  For special operations the stress training is increased tenfold.  No sleep, lack of food, cold waters, and also the ability to complete the mission.

Stress is a quintessential key to value.