Next time you’re in a bad mood, this might make you feel better: Australian researchers say that grumpy people are remarkably better at critical thinking than the annoyingly happy people around them. In other words, a bad mood makes you better at making decisions. You’re also less gullible, and less likely to fall for a con job than when you’re happy.

Why? Because a bad mood literally makes you more skeptical. Lead study author Dr. Joe Forgas says that cheerfulness promotes creativity, flexibility, and cooperation. But happiness also makes you more likely to take mental shortcuts, which means you can miss things. On the flip side, a gloomy mood makes you a more attentive, and careful thinker, which means you’re more likely to pay attention to what’s going on around you. That makes you better able to focus and consider all the relevant facts.

In the study at the University of New South Wales, volunteers watched either an upbeat or depressing movie. Then each volunteer was asked to complete several tasks, including judging the truth of urban myths, like whether forwarding a specific email to 200 friends will earn you a free iPad. And providing an eyewitness accounts of an event – like a staged purse snatching. The result? Those who were in a bad mood made fewer errors, saw through more urban myths, and made better eyewitnesses. They were also better able to communicate the details of what they saw. And were much better than happy people at using a written argument to state their case.