She soon forgot about all the other things that were so wrong. I guess it was because she just wanted to believe rather than weighing up the evidence. |
It's a consequence of how our brains work.
It has been well demonstrated that we remember things expressed positively more than we remember things expressed negatively.
Thus we count the hits and forget the misses.
If the situation is reversed, i.e. you are looking for the medium to get it wrong, you will likely underestimate the number of times they got it right - because again you will count the 'hits' (getting it wrong) and forget the misses (getting it right).
If you are aware of our tendency to do this, then you can counter it a little, or at least know to look for third-party independant corroboration to double-check the impression you have,