and you didnt notice that your ambient temparature is constantly changing and that your body is constantly adapting to that by increasing or decreasing your metabolism(unless you are a cold blooded organism).
I don't think human skin is a good conductor of heat and bones are definitely not. That little bit of sensing heat is negligible to the variation of metabolism that is always happening. Put it this way: You can put your hand on a 70 degree C water. It will hurt but it is definitely possible. Gradually, keep on increasing the temperature. At one point, your hand will not tolerate the heat anymore and you will remove it. Had your body adapting it by varying metabolism, you could have kept your hand on practically any temp that way.
Ps. this is not a biology class.
Moral of the story is I can feel temperature ranges that I work with in real life and and I have proven myself to be true various times and my friends agreed too. What I did was I was touching the heatsink and did not look at the monitor screen. I told my friend an estimate of the temp that I feel. He checked with softwares and I was real close and the range I told in which it lied was perfect.
These things are relative to human beings. I would not be surprised if you can tell at what RPM(a range) a fan is spinning just by looking at it. For me, I would not have a damn clue.