I never felt a need to attain extreme speeds in order to enjoy a ride, maybe it's just my instinct for self preservation. I have a physically demanding job which requires me to be in top physical condition and already has enough risks and I just can't afford injuries from cycling and other hobbies. A small injury can make my job very difficult, a serious injury would prevent me from doing my job. Let's get real here, injuries have a serious affect on your overall quality of life. Racers who get paid to ride are a different breed, they do this for a living, they can afford getting injured, I can't...Anything over 30 MPH is just being foolish and tempting fate, I have no need to go any faster than 30 MPH and that only happens occasionally when going downhill. When I reach about 30 MPH I start tapping the brakes and limiting my speed to prevent from going any faster. I ride singlespeed and live in flat to rolling terrain with an occasional steep hill so it's pretty easy to control speed.