 I was going to say smoking, and I'm going to go with my number two, suntanning. The sun. Number nine, skipping sunblock. Jesus. Even when it's cloudy, skin-damaging UVA and UVB rays still increase risk for drilling skin. I'm feeling good about this list. Skin cancer. If broad-spectrum sunblock feels too thick to slather on every morning, find a daily moisturizer off the same protection against UVA and UVB rays and use it year-round.