I don’t start my showers cold, but always end them so. I start the shower warm, then switch to hot, then at the end as cold as possible for about half a minute. In the beginning it was mildly uncomfortable, but I’ve become accustomed to it quickly. Showering in different places, I’m often surprised at the range of different temperatures of the coldest water available.
A cold shower really wakes you up. It closes your pores, which is good for the skin, and prevents heat loss. After a cold shower, you’ll always feel great about yourself.
Interestingly, ending with cold showers is perhaps the only positive habit I’ve built recently. I usually find forming habits challenging. This one didn’t require much work at all – usually I’m good at finding excuses, the easiest one being “I don’t have time for this”, which doesn’t apply here. Yes, I do have half a minute (and so do you, you’re reading this after all).