Use your imagination, my dear psychologists! You might be right that the pain of losing $100 is more intense than the happiness of finding $100, but think about the following:
The happiness of finding the $100 you lost is more intense than the pain you felt when you lost them.
5 December 2017
This is what Nassim Nicholas Taleb wrote in Antifragile :
Few objects bring more thrill than a recovered wallet (or laptop) lost on a train.
Great minds think alike, don't they?