This paper studies whether opposite opinions about an important, yet payoff-irrelevant topic offset the well-documented positive effect of communication on cooperation. In an experimental setting, we exogenously vary the importance of the topic, and the subjects' ability to communicate. We hypothesize that disagreeing on an important topic can counteract the cooperation-enhancing effect of communication. Furthermore, we argue that communication gets unfriendlier and cooperation becomes less likely if subjects have opposite opinions about a topic of higher importance.