I can see how this paragraph might be bothersome to some of the Holy Father’s critics, and to those who have reached some sort of limit where their expression of good manners and courtesy are concerned.
266. Good habits need to be developed. Even childhood habits can help to translate important interiorized values into sound and steady ways of acting. A person may be sociable and open to others, but if over a long period of time he has not been trained by his elders to say “Please”, “Thank you”, and “Sorry”, his good interior disposition will not easily come to the fore. The strengthening of the will and the repetition of specific actions are the building blocks of moral conduct; without the conscious, free and valued repetition of certain patterns of good behavior, moral education does not take place. Mere desire, or an attraction to a certain value, is not enough to instill a virtue in the absence of those properly motivated acts.
For your reference, remember that Amoris Laetitia is online here.