How affect some effects
Everybody knows it, everybody loves it. It is used in medicine, when patients receives pills with neuter action, but they are told it is a treatment. Even many times it cures the symptoms, not the disease, it is incredible what we can do with our mind.
A hundred years ago, when India was a British colony, the number of cobras was a serious problem in the cities. The governors decide to pay for each head of cobra brought. Soon, the population of cobras decreased, but some people with entrepreneurial spirit started to raise in order to get money for their heads. When the governors found out(they wouldn’t like to waste money this way) put the new business men to release the cobras in the forest. In the end, the population of cobras increased very much.
The Boomerang Effect
In psychology, when you try to convince someone, it's possible exactly to get the opposite. That's why a good strategy might be "Reverse psychology", meaning to have a goal in expecting that the other person would do everything different. It works excellent on persons with a huge vanity.
The paradox of choice
Many choices can create confusion, so less options could bring more happiness to a customer for example.
After a long time playing, people imagine they put the forms together. This is available in other game, as well. It can be fun when you try to arrange different objects in the stack.