Here's is a condensed and probably shabby explanation. Steeper head angles, make the steering quick, responsive and agile. Too steep, and the bike get's twitchy, and braking can be an adventure. Shorter chain stays keeps weight over the wheel when climbing out of the saddle, but the bike get's a little less stable, and doesn't trail as well. Top tube length affects the riders position, comfort and distribution of weight on the bike. seat tube angle affects the relationship of the rider to the pedals.