Have you ever actually yelled at kids to get off of your lawn?
Reluctant admission, I actually have..this spring. I ran them down a bit later and apologized for being a bit dickish, but re-iterated that they needed to stay out of my fucking lawn and driveway.
How am supposed to know just how fat and out of shape you are? If seen some goofy gorillas manage proper cycling form. If you're sitting in your ass you probably aren't getting a good enough workout to make much difference.
That's because you shouldn't be putting that much weight on your ass, it's a saddle not a seat. In other words, you're riding your bike wrong, have the wrong size of bike, or have the wrong bike for your style of riding.