I like a hot shower, but I have nothing on my wife. If she entered the shower with a live lobster, it’d be ready to eat by the time she emerged.
Coupled with that, she tends to switch on the bathroom heater when she showers, while I only turn on the fan. I like the air to be cool when I exit; if the heater’s on, I just about pass out.
That’s what lotion is for after I finish parboiling myself.
Add me to the “continuallly adjusting upwards so it’s always just shy of scalding” group. It’s not a real shower til I break a hard sweat and clear my pores out. 
I’m more of the school that it’s not a real shower until I can trigger heat-induced histamine release in my skin and give myself a good scritchy while washing/exfoliating. Resets the ol’ mast cells for the day and DEEP CLEANS.
I eschew moisturizers (I’m too moist to begin with) and find hot showers make me just right!
You must all be a bunch of gree-eee-eeasy people 
I constantly turn the heat up as I shower. I like a burst of hot-as-I-can-stand-it right before I quit.
Ignoring super modern water heaters that turn the temp down when they aren’t being used…most t-stats, even the ones for your home heating and cooling have something called a ‘swing’. This allows the temperature to fall X degrees below the set temp before tripping the t-stat at which point it calls for heat. It would then have to rise to X degrees *above[/] the set temp before shutting off (and the opposite for cooling). This is to prevent the unit (furnace, AC, water heater, refrigerator etc) from constantly cycling on and off and on and off trying to maintain an exact temperature.
What you’re doing is tricking it. If your water heater is normally at 120, you’re running just enough cold water out of the unit to get it to fire. It’ll then stay on until it gets up to 120 plus (half the) swing temp. IOW, yes, it’s a few degrees hotter.
PS, if you look at the directions for your HVAC t-stat the swing temp is usually user adjustable, but unless there’s an issue you typically want to leave it alone so you don’t put extra stress on your equipment.
I keep my hot water set on a level at which I can (just barely) let it fun fully hot on my hands. If I want it cooler than that (say, for a shower), I add cold, and how much cold it takes varies by season of the year.
Thank you Joey P that explains the behavior perfectly.
I never knew I had a water heater that was a swinger!
I do what the OP does–start it what seems hot, then keep cranking it up and cranking it up until I run out of hot water or get tired of standing in hot water (never!).
But…when I wash my hair I turn it to cool to rinse the conditioner out, because I have heard this makes your hair more manageable and my hair needs all the manageability it can get. It’s long hair though, so easily possible to cool off my hair without hitting too much of the rest of me with cool water.
Since its winter right now for most of us, aren’t you all talking about taking these *hot *showers during the cold winter months?
Don’t you adjust the water temperature of your showers during the summer compared to now?
[QUOTE=Joey P]
Frog in boiling water and all that.
[/QUOTE]
Well yes.
I feel like I get habituated rapidly to the water temp in the shower, and by the end of a relatively brief one (several minutes) I crank up the temp for 30 seconds or so. This feels soothing on my back and produces a warm glow which lasts a short time until I realize I’ve got to step out, dress and go to work. 
Me too. One of the worst things about shaving one’s legs is knowing that once you turn off the water temporarily so you don’t wash away all the shaving cream before you mean to you might not get it back to the exact spot where you’d been happy with the temperature.
Not really for me. I make liberal use of the a/c in my house, so unless I’m showering directly after coming in from summer misery, my shower temp has nothing to do with the weather.
I once went thirty days with no hot water (I was moving, notified my utilities two months ahead, and the gas company fucked up).
I went with “whatever doesn’t kill you makes you stronger” and didn’t bother having the gas turned back on. Boy did that suck. Ice cold showers every day. It was actually difficult to breath.
I will first respond to the OP.
(1) No, I rarely change the incoming water temperature.
(2) I think you are getting used to the temperature.
My situation is unusual. I live in a solar heated water household. So hot water is provided by the sun in an 80 gallon storage tank. I need to mention the “how hot can he/she take it” issue. Eight months of the year the sun does all the work here and routinely heats our domestic hot water to 140 degrees F. If you take shower in that temperature you will be scalded and injured – badly.
We do not use any temperature regulating apparatus. So we religiously warn visitors about the water temperature. There have been no surprises but I will say that a few of our visitors have remarked how much they enjoyed taking the hottest shower they’ve ever had. And for as long as they want, because we have that big tank.
I think it worth noting that while none of our visitors have been scalded, I have. Not in the shower. But doing dishes and other kitchen work. Whew! Having really hot water is a good thing – but watch out!
Alright. Having employed some pseudo-science and a less-than-rigorous methodology, I’ve come to the tentative conclusion that the issue is more me than it is the shower. I took several measurements over the course of an approximately 18-minute shower, each time using an eight-ounce glass (filled about three-quarters with water right under the showerhead) and an analog meat thermometer. Before taking each measurement, I made sure that the meat thermometer was back to reading room temperature. Here’s what happened:
[ul]
[li]First Measurement: taken just before stepping into the shower at a temperature that felt hot-but-comfortable to my hand — 98 degrees.[/li]
[li]Second Measurement: taken after the first adjustment upward to make the shower “hotter” — 101 degrees. [/li]
[li]Third Measurement: taken after the second adjustment upward to make the shower hotter — 105 degrees.[/li]
[li]Fourth Measurement: taken after the third adjustment upward to make the shower hotter — 105 degrees.[/li]
[li]Fifth Measurement: taken before the fourth adjustment upward to make the shower hotter (to see if temperature had actually dropped) — 101 degrees.[/li]
[li]Sixth (and Final) Measurement: taken with shower knob at maximum heat, with water temperature no longer warm enough to feel good — 100 degrees.[/li][/ul]
So even though there is evidence that the water temperature in the shower had some downward momentum (at least by the end of the shower), the most important stat to me is that my exiting temperature of 100 degrees was warmer than the temperature when I first got in, which felt good at the time. So my body is definitely adjusting to the heat, regardless of what else the shower is doing.
I also would have assumed I was taking showers with hotter water than that. Granted, I don’t know how accurate the meat thermometer is for this purpose, but I would have guessed a higher number.
I too would be curious if a (non-calibrated) meat thermometer was accurate at such low temps AND and such good resolution that it could tell the difference between 101 and 100 degrees.
Assuming it can, your results suggest that you exited the shower because your body was used to the temp, not because it had fallen so much that it was actually cold. Even if your thermometer is incorrect, I’d guess that no matter what it said, it’s probably saying the same thing at for the same temp water, or within a range of degrees. That is, maybe you got in at 100 and got out at 99, but it’s not that you got in at 110 and got out at 85. Even if it’s not accurate, as long as it’s precise, the numbers are irrelevant. You could have just made a mark on the dial where the pointer was when you got in and looked to see if it was above or below that line when you got out…if it’s precise.
Real data!! I love the smell of science in the morning!! 
Warts and all.
I’d agree with Joey: the accuracy of the meat thermometer would initially be suspect at that low temp. But the repeatability should be good; far better than your perception of temp while in the shower. So that supports your data and therefore your conclusions.
Second item: Most recommendations for hot tubs say not to exceed 104F. Much more than that, even 108F, is hotter than people can stand to get into, much less stay in for more than a couple minutes without risk of internal overheating.
To be sure, there’s a big difference between the heat transfer of being fully immersed in a large tank of 104F water versus being sprayed with small droplets of 104F water that are cooling quickly as they fly a couple feet through the 70-80F air, evaporating all the way.
If your thermo had said 80F or 120F I’d have said it’s way off in accuracy. The fact it’s showing the high side of 100F is pretty good corroboration that it’s in the infield, not just in the ballpark.
I do basically the same thing. I like hot showers and will drain the tank. I keep cranking up the heat because my body adjusts and because there is less hot water so I have to compensate.
ETA: Data! That’s awesome! Kind of validates my impression.