Seriously going to tell you a lot of people don't know this, but that's not universal. If everyone knew everything, the internet would be all cat videos.
In a related idea, skin is much better at judging differences in temperature than it is at judging actual temperature. Not exactly the same because this is more dependent on temperature gradient rather than the rate of transfer. Because of this, when you use you hand to judge if a child might be running a fever, instead of just touching the child's head, it is better to place one hand on the child's head on one hand on your own and compare. The idea is that if you're not running a temperature, you'll more readily notice if the child's temperature varies much from your own, providing a point of comparison rather than a subjective "he feels warm". Of course, in this day and age, most of us have a thermometer handy at home. But sometimes you're not at home.