If your friend is feeling down, your first thought might be to tell her things aren't so bad—but that may not be helpful. People with low self-esteem get a much bigger boost from "negative validation" than from "positive reframing," suggests a study in the American Psychological Association out of Canada's University of Waterloo. What does that mean? They'd prefer for you to tell them that you understand their feelings—and that those feelings "are normal and appropriate to the situation"—than for you to tell them to put on a happy face.
"People tend to be uncomfortable dealing with negative emotion, so we believe it’s best that everyone thinks positively, and we try to make them think that way," researcher Denise Marigold tells Pacific Standard. We might think we're helping, when in fact we're just making the other person feel alienated, she explains to Today. "They feel as if people don’t understand their issues and don’t accept their feelings." That doesn't mean you should agree with your friend's low self-opinion; instead, just show your empathy. A teddy bear might help, too.