News Flash #1: Iowa is NOT hilly. Yes, yes, yes, I've been to the Loess Hills, I've been to Dubuque, I've seen and ridden the bluffs that dot several regions of our fair state. But when you look at places that have REAL hills (heck, even the baby hills of Western Pennsylvania, where I learned to love my granny gear nearly as much as my own Granny), the most defining geographic feature of our state is its pool-table flatness.
News Flash #2: When you are doing your "training rides" in Central Iowa, your inspirational soundtrack of Hootie & The Blowfish/Lynrd Skynrd/ESPN Arena Rock 7/Best(?!?) of Garth Brooks does NOT need to be broadcast to ALL of Central Iowa. If your iPod's anything like mine, it came with a set of headphones. Try 'em. It's a pretty safe bet they won't make you any more clueless or less aware of your surroundings than you already are.
News Flash #3: There's a better-than-average chance that the fact you weren't aware of News Flash #2 explains the fact that you also missed out on News Flash #1. In other words, maybe Iowa wouldn't FEEL so hilly if you weren't dragging an abandoned hayrack loaded down with a Marshall stack and enough car batteries to send a Prius to Mars.