Mental models on:

optimization

A/B Testing

We must learn what customers really want, not what they say they want or what we think they should want - Eric Ries

Mental Model of Flow in Sports

In a state of flow, people are so involved in an activity that nothing else seems to matter; the experience itself is so enjoyable that people will do it even at great cost, for the sheer sake of doing it. - Mihaly Csikszentmihalyi

Law of Diminishing Returns: Optimizing Efforts

We reach a point, in other words, where the law of diminishing returns kicks in, and more becomes too much.