What makes fishing as a hobby so appealing that people will fish all hours of the day and in nasty weather?

I saw some people fishing the other day in 16 degree Fahrenheit (-9 Celsius) weather at 4:30AM. They were not ice fishing with a little hut, but standing at the base of a bridge with no shelter or campfire. People are at that bridge fishing regularly when it is cold but that was the coldest temp I have seen so far. Why is it so...