Nearly half the time we’re awake, our thoughts drift to topics unrelated to whatever we’re doing. We think about the fight we had with our spouse when we’re driving or replay events from a friend’s wild party while brushing our teeth in the morning. We text incessantly while watching TV and phone mom during laundry-folding time. And all the while our minds are wandering—even when we’re having pleasant daydreams—we’re not very happy, according to a new study published today in the journal Science. “How often peoples’ minds wander is definitely a big predictor of who’s happy and who’s not happy,” says study author Matthew Killingsworth, a doctoral candidate in psychology at Harvard University, because the more often they take themselves out of the present moment, the less happy they are.