According to Nobel prize-winning psychologist Daniel Kahneman, we humans are very poor decision makers when it comes to our own happiness. The problem begins with language. We use the word happiness, Kahneman says, to refer to two very different and often mutually contradictory phenomena: the mood of the moment and our overall life-satisfaction. The former is an evanescent and notoriously unreliable gauge of the latter. Example: the joy of buying a new car vs. the subsequent, ongoing annoyance of paying the monthly bills.

Kahneman’s decades of cognitive research, much of it done in collaboration with longtime colleague Amos Tversky, has shown that humans are subject to what he calls a “focusing illusion.” We focus on the moment, overestimating the importance of certain factors in determining our future happiness and ignoring the factors that really matter.

As if blindness to our own tendencies to err weren’t bad enough, we’re emotionally committed to our bad decisions because of another bad habit Kahneman has identified – the tendency to trust our snap, intuitive judgments over better, more deliberative decision-making processes. Like all cognitive illusions, this one has a vestigial, evolutionary component: quick thinking keeps you safe from predators.

The sobering take home lesson here is that in some crucial areas, we don’t know and we can’t fully trust ourselves. On the bright side, Kahneman’s work shows that the kinds of errors we tend to make are extremely predictable. While studying our own cognition may never completely free us from its traps, it should at least give us pause to reflect and distance enough to make a few better decisions.