Yesterday a friend was telling me about her commute. Going home each day she has 6 km of hills. I don't know the total elevation gain but it's a rough way to end the day. She said that part of what keeps her going is that right around the point where she'd love to quit there's a big ad for a gym with a picture of a person riding a stationary bike in the gym. That reminds her that she's outside actually riding a bike, instead of driving to the gym to pay to ride an exercise bike indoors.