Check out the following exercise, guaranteed to freak you out. There's no trick or surprise. Just follow these instructions, and answer the questions one at a time and as quickly as you can!
Again, as quickly as you can but don't advance until you've done each of them... really.
Now, arrow down (but not too fast, you might miss something).........
Now repeat saying the number 6 to yourself as fast as you can for 15 seconds, then arrow down.
QUICK!!! THINK OF A VEGETABLE!
Then arrow down.
You're thinking of a carrot right?
If not, you're among the 2% of the population whose minds are warped enough to think of something else. 98% of people will answer with carrot when given this exercise.
(I thought cucumber. I have no idea why carrot was the theme.)