My son has been in the dating parsha for a couple of years. Across the board, the number one complaint (maybe the only complaint I have ever heard him express about any girl he has dated) is their failure to express a simple thank you. He does not believe in going to lounges, and puts a great deal of thought into planning a date where they can get something to eat and be able to talk and get to know each other. He tries to arrange for interesting activities, and is very solicitous of their having a pleasant time. One of the girls with whom he was set up was the ONLY one to express her appreciation for his obvious thoughtfulness. Though it ultimately did not work out for hashkafic reasons, he liked her very much for showing this middah.
There is no excuse for the inability to be makir tov. It is NOT something that goes without saying, it has to be expressed. Hashem knows exactly what we are thinking 24/7, yet we start each morning off with MODEH ANI. It is a foundation of our character. If we cannot be makir tov to other people for the obvious things they do for us and of which we are fully aware, how can we properly be makir tov to Hakodosh Boruch Hu for the million and one things He does for us all the time, that we take for granted?