Yes. A bike frame that is too large for the rider will put them into an uncomfortable stretched out riding posititon. Their feet may not be able to reach the pedals while pedaling. You run the risk of hurting yourself if you get off the saddle too fast and drop onto the frame top tube. A bike frame that is too small will also be uncomfortable to ride. You will feel too squished by the handlebars and won't be able to turn the bike easily. Your legs won't be able to extend properly while pedalling. You will get tired quick and get sore knees from pushing too hard with bent legs.