I understand what you mean, however, I guess what some people might refer to as "fake" is not just the act of being cordial...but going out of your way to sound cordial even when you don't really mean what you're saying, especially if you actually feel the opposite from it. Ex. saying: "Wow, I love your hair! A short hairstyle looks really good on you!" really thinking: "ugh, that's so ugly. It makes her face look fat." That could be considered a white lie, but when applied to something like love for example, it could really hurt or upset others when they actually believe the cordialness lol Ex. boy says "I love you, you're the woman of my dreams." girl says "I love you too, I want to be with you forever." but really feels "I think I love you...at least as a person...I don't want to hurt him, maybe I'll grow to love him in time." but eventually gets over him and moves on breaking his heart not sooner, but later.
The moral of the story: You may have good intentions and sugar coat a lot of stuff for sake of sparing other's feelings now or getting them to like you. But in reality, the truth usually comes out and a lot of the times it hurts...that's life.