Are you a victim of “inattentional blindness?” A great piece in the Daily Telegraph describes:

Working with Christopher Chabris at Harvard University, Simons came up with a demonstration that has now become a classic, based on a videotape of a handful of people playing basketball. They played the tape to subjects and asked them to count the passes made by one of the teams.
Around half failed to spot a woman dressed in a gorilla suit who walked slowly across the scene for nine seconds, even though this hairy interloper had passed between the players and stopped to face the camera and thump her chest.
However, if people were simply asked to view the tape, they noticed the gorilla easily. The effect is so striking that some of them refused to accept they were looking at the same tape and thought that it was a different version of the video, one edited to include the ape.
Here’s the original video

The mind sees what it wants to see; indeed. This prompted me to think about how little we question what our mind comes up with.  Just like there are optical illusions– your eyes are convinced they’re seeing things that are not there– there can be thought distortions; your mind convinced of the truth of its thoughts.  (for more on why certain distorted thoughts can seem so valid, see Jill bolte Taylor for the chemistry & neuroscience behind this process).

Not that long ago we were convinced the earth was flat. It seems silly now. But why should we be so certain of the solidity of any of our other convictions? This applies to your thoughts about the world, about other people, and equally about yourself. Just because a thought is in your mind doesn’t mean it has any validity.

One useful way I’ve found to think about it is to see thinking as just one of our abilities.Seeing is what your eyes do. Hearing is what your ears do. Thinking is what your mind does. No more, no less.  We wouldn’t want to do away with our thinking, any more than our seeing our hearing. But we shouldn’t give it any greater credence either. You don’t take the sights you see to be a verdict of who you are (if you see an ugly sight, you don’t take it to mean that you’re an ugly person).  The same could be said of your thoughts.