Answer by Nishad Shah:
Consider a simple example. In the following figure, look at images B and C.
Who do you think is a better shooter of the two ?
Intuitively, most people will say B. Why ? Consistency.
When arithmetic mean is just a measure of the average score, standard deviation pretty much gives an idea about the consistency of data. So, while arithmetic mean of C is close to the bull's eye, he isn't a consistent shooter or more random. Where as B is too far away from 0, but still is consistent with his shots.
Which means B is a better shooter than C.