For street bikes the set-up is slightly different, see below. This version is from HyperPro, a large Euro suspension specialist
The way they describe them is -
Motorcycles with a short wheelbase and an aggressive steering geometry provides the ability to make very quick changes in direction. As a side-effect it the bike is less stable, gives less feedback from uneven road surfaces, and is more difficult to control. If the front wheel is not completely inline from the direction of travel when it touches down after a small wheelie, it may cause an unwanted wobble.