In all of the years I’ve worked as a psychotherapist this is one issue that cuts across sexes, age, status, wealth and just about everything else. If you “stuff” something, meaning you don’t tell the other person what you’re thinking or feeling for fear of upsetting them, there will eventually be some fairly serious consequences to you like major depression or anxiety, or drinking too much or self-soothing with food, etc. or to the other person in the form of out of proportion anger or an emotional blowup from you. Something that might have been a manageable issue if was handled right away gets “stuffed” and over time more and more unsaid issues combine into a not very pretty picture. The point being that not being able to say what you think to another person because you’re afraid to hurt them or make them mad will have consequences to you and to them. Most people just don’t want to hurt the other person’s feelings, an admirable idea, and they don’t know how to say something critical in a way that the other person will hear without getting upset. This is an interesting article containing tips about how to criticize in a positive and helpful way.

http://science.howstuffworks.com/life/inside-the-mind/emotions/criticize-without-jerk.htm