Have you noticed that some people just steal the light from the day? They always have to see the worst in everyone and everything. As a result, they are pretty miserable to be around. If you argue for the best, it can be adversarial and grim. Try basic conditioning methods, reward them with your attention every time they talk about something constructive, positive or uplifting. Withdraw your attention when they start to carp. If subliminal messages don’t work, issue a challenge, “let’s get through this evening without saying a bad word about anyone”. (Unless you are discussing evil dictators!)
