When the boss wishes me a good morning, the proper response is 'And good morning to you', not 'Go to hell, asshole'.
When I get a text from my wife telling me how much she loves me and appreciates me, the proper response is 'I love you too', not 'Yeah, who is this again?'.
When the traffic clerk at work tells me that tomorrow is her 60th birthday, the proper response is 'Well, happy birthday! Really, 60? I would have never guessed' not 'Damn, you got less than 20 years to live.'