Human life tends to flourish in the balance. Most of our planet fits that description. As long as you stay away from the South Pole and don't fall into a volcano, Earth is a pretty comfortable world.
Space is a radiation-dominated environment.
Objects heat up by absorbing sunlight and they cool off by emitting infrared energy, a form of radiation which is invisible to the human eye. As a result, insulation for the International Space Station doesn't look like the fluffy mat of pink fibers you often find in Earth homes. Here on Earth, we use blankets containing aluminized Mylar to wrap people who have been exposed to cold or trauma. This ensures radiation will be the most dominant heat transfer method through the blanket. It's something we have to design around.