I AM FAT!
One of my last bikes as a kid was a Raleigh English Racing Bike. It had thin tires and a 3-speed shifter.
I took it to a service station once to air up a tire. Being a bit ham-fisted with the air hose, I exploded the tire in my face. I was covered with black powdered rubber and bits and was psychologically scarred for life.
I had to carry the bike about 10 blocks to get it back home.
I still can't air up a tire without worrying about it exploding.