Flat is relative! I'm originally from Illinois, and dang, there is not a hill in sight where I used to live! When I first started riding in Michigan i thought the hills were HUGE (ha ha). I still have some trouble with the bigger ones, but I'm looking forward to trying some real hills in California this summer (if i don't die trying to climb them!)
...i need one of those "Hill Slug" t-shirts and/or jerseys!