Do Klingons get depressed?
Think about it. What would a depressed Klingon be like? Would it, could it, happen to them? Klingons are all about honor and glory and being a proud warrior, we've all seen it. Would it be considered dishonorable or weak for a Klingon to get depressed or sad?
It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shakes, the shakes become a warning. It is by caffeine alone I set my mind in motion.