I've always been interested in the perception-reality mismatch, and here is a telling experiment-
Looks Can Deceive: Why Perception and Reality Don't Always Match Up: Scientific American:
"The Witt-Proffitt team published another report on the observation, well known in sports lore, that baseball players perceive the ball to be larger when they are hitting well and smaller when they are on a losing streak. Since then, Witt, now a professor at Purdue University, along with her student Travis Dorsch, has pursued this intriguing link between how success (or lack of it) in a task affects one’s perception of the world.
In their experiment, 23 volunteers had to kick an American football through the field goal from the 10-yard line. After a warm-up, participants were asked to judge the height and width of the goal by adjusting a handheld, scaled-down model of the goal made out of PVC pipes. They then each performed 10 kicks. Immediately after the final kick, participants repeated the perceptual measurement.
The result was striking. Before kicking, both groups had the same perception of the size of the goal (incidentally, an inaccurate one: everybody underestimated its actual width-to-height ratio). But after 10 kicks, the poor performers (those who scored two or fewer successful kicks) saw the goal as about 10 percent narrower than they had before, whereas the good kickers (those who scored three or more) perceived the goal to be about 10 percent wider. How well you have performed over the past few minutes influences the way you see the world! Not just metaphorically, but on a physiological level—it changes your actual perceptions.
After more data mining, the two psychologists discovered that the people who missed the goal because they tended to kick the ball too short perceived the crossbar as being higher than did their more successful peers, whereas those who missed because they kicked wide judged the upright field posts to be narrower."
