I had similiar feelings initially about spinning, but lately have noticed a change. It comes from experience riding and an increased base fitness--from training for an riding full and metric centuries. There is probably a name for the phenomenon. It seemed that as I have reached a certain level of ability/fitness, my spinning has become more effective. One day I thought, "oh, so THIS is spinning!" Not feeling that it was ineffective, but like it was actually working. I was riding against a headwind the other evening and it really worked. I was also playing with riding way down in the drops and spinning, and it was so fun!
The bicycle is the most civilized conveyance known to man. Other forms of transport grow daily more nightmarish. Only the bicycle remains pure in heart. ~Iris Murdoch, The Red and the Green