Read the following text:
Finished Files are the Re- sult of Years of Scientif- ic Study Combined with the Experience of Many Years
Got it? Makes no sense, huh? Don't worry about that. Read it again and just count the number of times the letter 'F' occurs.
How many did you count?
If you counted less than six, go read it again and count the number of times the word 'of' occurs. In a group of 20 people, 2/3 of them will see the letter 'F' occurring only three times. Often, you can have them read the paragraph over and over and they'll still miss the word 'of.' You probably get the idea, but in a group of people, it's a pretty dramatic example of how all of us perceive reality in different ways.
[Source: The Secret Art of Managing Your Boss, part 1 -- I'm curious to know why most people, including myself, ignore the 'of' in this test.]