I came to this thought because of long hours of frustration due to the blatant ignorance of humans (in myself and in others). Its purpose is to prove the folly of hating ignorance:
Imagine if humans always did "right," but had no understanding of "wrong." We wouldn't really be anything -- perhaps only beings with no purpose. The fact that we have the capacity for both right and wrong requires us to choose one over the other and, naturally, we have the desire to be right. This desire requires us to find out what "right" is, which requires the ability to implement reason in constantly challenging our basic beliefs. (Paranoid religious belief is the result of the absence of reason.) In our search for what is right, we come to deeply understand why something is right or wrong through the use of our own thought. The greatness is in the understanding of the doing, not merely the doing.
(A side note: this is analogous to the idea of a capitalistic, unregulated society, in which the government's only job is to protect the basic rights of the citizens. If people are allowed to fail, they have much more of an incentive to succeed. When they are given rewards for failing (i.e. welfare), they are demeaned because their want to succeed is replaced with contentment in failure. In other words, they are not required to use reason in order to survive, and therefore become comfortable with their ignorance.)
The point is: humans are great not because they have the capacity to be right, but because they have the capacity to choose right over wrong.