The Importance of Sincerity in I Ching Practice

Sincerity is essential to effective practice. 

The I Ching is interesting in how it has various ways to make it harder for you to lie to yourself, but it is not fool-proof in that regard, since someone who really wants to get a result that just tells him what he wants to hear will find ways to 'cheat' to do it.

In the Magician's I Ching Facebook Group,  there had been a discussion on the question about whether a casting could ever be wrong.
It was argued that it could not.

I would definitely agree: an I Ching casting, if performed correctly, will not be wrong.
Technical error or imperfect methods can make it less accurate.

But that aside, the problem is in two things: the question before the casting, and the interpretation after the casting.

If you are asking the wrong question, or asking a question in an imperfect way, the I Ching's result could be wrong (de facto, rather than de jure; it will be the right answer to the wrong question in the first place).

If you ask the right question but lack either the ability or the will to interpret it correctly, then we will be unable to make use of the (correct) answer.