I came back from Germany last month, and after seeing how the Germans get in and out of cold baths, I decided I need to attain this ability.
So I haven't had a warm bath/shower for about 2-3 weeks. I turn the dial all the way to cold, so I'm getting water at the temperature it's coming from the mains water supply, which isn't too bad now in the month of August in Ireland, Europe.
I take the cold water in 4 steps: 1) Back pelvis, 2) front pelvis, 3) glutes and entire legs, 4) everywhere else
Even after having been doing this for 3-4 weeks, I still feel a little apprehension going from Step 3 to Step 4, but the first 3 steps are enough to motivate me into Step 4
If you watch YouTube videos and read testimonies of people who only take cold showers talking about all kinds of 'methods' with Dutch/German/Scandinavian people's names, they tell you that you'll reach a point where you look forward to taking a cold shower. I think these people might be telling white lies to motivate people, because after 3-4 weeks, I'm still not looking forward to them -- in fact I'll put it off til I need to get dressed to leave the house.
Those 2 minutes of turmoil in the shower in the morning are worth it though. Primarily I'm interested in the psychological effect, it makes you more resilient. There are other benefits too though, feeling refreshed, closing your skin pores, raising metabolic rate, boosting the immune system to make more white blood cells.
I'll let you all know if I ever look forward to taking a cold shower -- it might never happen. For the time being I'm content that the 2 minutes of turmoil is worthwhile and I don't regret it.
I'm hoping I can keep this up going into Autumn and Winter. In Wintertime, the tap water in Ireland is very cold (you need to let it rise to room temperature before putting in a goldfish), so I'm hoping that over the next few months, I'll be able to blissfully tolerate colder and colder water. I really hope I can still take a cold shower in early January.