Most of us know (or are part of) that couple that swears by the benefits of going for a run together, but a new Swiss study has found indulging in bad habits makes a couple closer. Focusing on 3 groups of couples who either smoked, lazed around, or ate junk food, the University of Zurich researchers analysed diary entries written by participants over a month. The diaries tracked how often a couple engaged in those behaviours together and also saw participants rate their satisfaction with their relationship daily. They found that the couples who smoked and lazed around together reported higher relationship satisfaction the day after engaging in those behaviours, while those who tucked into junk food reported no change. Researchers reckon that’s because those activities are often used to relieve stress or improve mood, allowing partners to share what they consider positive experiences. Too bad it doesn’t extend to a junk food hangover…