It’s something everyone knows. If you’re rude to a cashier, you might just ruin his mood. He’ll be rude to a customer and could spread his negativity to her. Be nice, and the good vibes spread.
It’s important for activists to remember this. Aggressively attack someone for eating meat, they’ll attack you back and have a poor opinion or vegans and vegetarians. Respect their choices but explain the reasons behind yours and share some tasty food or recipes and you might just spread the good behaviour.
The world can be a very cruel place. Feminists and environmentalists know that all too well. Make an effort to change the world with a smile on your face. People will be more responsive and the world just might become a happier place to be.