Many users of AutoCAD do not like the new dynamic zoom effect in the application. When using the zoom window or zoom extents command, the drawing area zooms in or out very smoothly. It almost looks like a guided missile going in for the kill. If you do not like this new zoom look, there is a system variable that controls this "VTENABLE".
The VTENABLE system variable is set to 3 by default. Setting this to 0 will have the zoom command act as it did in past releases.