My knees have been aching and feeling a little odd, I think it's the cold weather (I commute wearing shorts). Where I live everywhere is flat and I find 52x17 single speed comfortable for commuting the rest of the year round.
Having read that back I think the lesson is not to wear shorts out riding when it's cold, it can make your knees feel odd. I was riding the same bike last year without complaint and while having to wear trousers to work.
The unbridled freedom and great pleasure that short-wearing brings is best left for leisure and warmer days.