Moods are infectious  — and that's official! (1) ... have proved that you can catch joy or (2) ... like colds or flu, whether you want to or not, especially at work. They have only recently started noticing that cheerfulness is also catching. John Addison, a department store assistant, was finding his work boring and (3) ... "The previous manager was (4) ..., and it was difficult to work when he was around," he says. "Then we got someone else who is funny and who gives out a lot of energy, and I suddenly felt much warmer towards the job."