When I was in the USAF in navigator training, I thought "it's OK to skip checking my parachute, and it's OK to listen to a rock station over the headphones instead of commands for the pilot." But I got a rude awakening. The pilot called a bail-out drill, which I missed until I noticed all the crew was around the back door strapping on their chutes. I ran back for my chute, and it wasn't there (I hadn't checked before take-off). The pilot had noticed that I didn't check for it, and hid it to teach me a lesson. I learned, but we also had to make an emergency landing so I could change underwear!