I think it is because you will stick with your favorite pattern and fish it harder. In your head, you know that it is a pattern that you can always depend on to produce and if for some odd reason it is not producing at a particular time, you do not remove it and try another pattern. Instead, you keep fishing it and trying to determine why it is not producing. You may decide you are not allowing it to go deep enough, allowing it to go too deep, retrieving it to slowly, to fast or maybe start twitching the rod tip while fishing it, etc. Whatever you do, you do not take it off because you just know that it will produce as soon as you determine how to fish it.

Once we feel we have answered this great question, we need to answer why one of our "never fail" patterns, all of a sudden, stops producing no matter what we do.