Dopamine is part of pleasure too, but most importantly it's "anticipation of reward" or how long you can focus on an action until your brain evaluates the resul

Dopamine is part of pleasure too, but most importantly it's "anticipation of reward" or how long you can focus on an action until your brain evaluates the result. This is what's broken in ADHD and why people affected profit from increasing dopamine with some stimulants.