Even when looking at everyday objects, our perceptions can be deceiving:
According to the New Look approach, first propounded in the 1940s by the influential cognitive psychologist Jerome Bruner, perception is largely a constructive process influenced by our needs and values. … [T]he desirability of an object influences its perceived distance.
90 undergraduates were made to sit at a table across from a full bottle of water. Half of the participants were randomly assigned to the “thirsty” condition, and given a serving of pretzels to eat. The rest were placed in the “quenched” condition, and told that they could drink as much of the water as they wanted. Both groups were asked to indicate how long it had been since they last had a drink, how thirsty they were and how appealing the bottle of water was. Finally, they were shown a 1-inch line as a reference, and asked to estimate the distance between their own position and the water bottle.
Their state of thirst had influenced their perception of distance, such that the water bottle was perceived to be closer than it actually was.
[O]ur desires have a direct influence on the perception of distance, such that desirable objects are perceived to be closer than they really are. This mechanism would serve to guide behaviour in the optimum way, by encouraging the perceiver to reach out and acquire the desired object.
Simple. Reach out and grab it. Unless, of course, someone is watching.