This example of exponential growth is taken from Margrit Kennedy's Occupy Money book.
Ask someone which salary option they would choose:
1. A $10,000 raise every week for one whole year.
2. A 1 cent raise every week which doubles each week for a year.
Most people would choose option 1, because it's easy to calculate. Even if they picked option 2, perhaps because they suspect that it's a trick question, they would be surprised to find that the amount of raise at the end of the year would be $45 trillion dollars.
This thought experiment shows how ill-equipped the human brain is at calculating exponential growth.