The majority of factory-sharpened knives come with a relatively steep bevel angle of approximately 25 degrees. This gives them an acceptably sharp edge, which retains its sharpness with considerable use, and ultimately keeps the consumer happy.
Improvements can be made to the sharpness of most factory-finished knives by decreasing the angle of the bevel edge slightly. Having a shallower angle will give a sharper edge; the downside is the edge will become blunt more quickly.
Machetes and axes have the steepest angle at approximately 35 degrees. A cut throat razor, at the other end of the scale, is approximately 15 degrees. An angle of 20 degrees is a very good compromise between sharpness and edge retention for pocket knives, tactical knives, and hunting knives.
The benefit of having a sharper edge is that less effort is required to move the knife through the material you are cutting, and more control and precision is achieved. This can be particularly useful when preparing food, filleting fish, field dressing animals, or doing any other knife work that requires some dexterity.
While it is difficult to measure these angles accurately at home, a good result can be achieved by taking the factory-set bevel and reducing that slightly.
To do this, rock the knife edge on a sharping stone and feel the angle of the current bevel. Lower the edge slightly and lock your wrist at that angle, feel the position and concentrate on holding it while you sharpen your knife.
There are two different sharpening techniques shown on the video. I prefer a combination of the circular pattern, which removes steel fast, and the traditional forward and backward motion to finish.