Dopamine reward signals in the brain are coded by how expected a reward is. Why? Because it's a learning signal. You've done something that you don't expect a r

Dopamine reward signals in the brain are coded by how expected a reward is. Why? Because it's a learning signal. You've done something that you don't expect a reward for, but get one anyway? Hey, dopamine rush, I need to notice that positive outcome and learn what happened because it might work again. Conversely, if you do something that you're used to eliciting an expected reward and nothing happens, negative outcome, dopamine crash - I need to learn about this disappointment. This post is a classic example (although there are other factors, such as the slowness of other teams who didn't know about the programme) - the people who weren't expecting a bonus were much happier with a much lower bonus. Add in the crappy way they hid the programme, so others didn't realise what was at stake and it was a recipe for disaster. If a bonus is expected it's not a "bonus", and only sets up expectations that lead to huge disappointment when it eventually doesn't happen.