To get to church on Sunday, I drive on a section of I-90, the same toll road I take to get to work. I-90, more commonly called the Mass Pike, has 3 lanes traveling in each direction. The speed limit from Boston out to Route 128 is 55 miles per hour.
On a work day, traffic in the left lane drives at 70 mph, the center lane drives at 65 mph, and the right lane at 60 mph.
On a Sunday, traffic in the left lane drives at 60 mph, the center lane drives at 55 mph, and the right lane drives at 50 mph.
What explains the Sunday speed limit? Obviously, people who are not as familiar with the Mass Pike are driving on it. There is also an overabundance of minivans on the road.
Same road, different people, different results
A good product minimizes the difference in ability. People of any ability should be able to use your product and get the same results.