It sometimes amazes me what people think constitutes adversarial conditions, and testing oneself. Reaching down and turning a knob, then telling yourself that you're building character? Odd.
By the way, I loved the comments. They read like something I would have written as a twelve year old. "I'm like a Navy SEAL because I beat myself up every day with a cold shower! I'm tough!" My favorite is paleo guy:
But I also do it due to the paleo/primal lifestyle I’ve been adopting—the fact that we didn’t evolve bathing with the convenience of hot coals or temperature faucets and and that our bodies are probably designed to buck up and shower in less-than-ideal conditions.
Except that you'll find that frequency of bathing, and bathing as a social and relaxation mechanism, directly correlates with availability of hot water. Where there are hot springs, there are happy, relaxed locals.