Telling the truth can be really, really hard sometimes. It can be uncomfortable because you want to make other people feel good (or, you at least don’t want to make them feel bad).
But if you withhold the truth, you are actually hurting them. How can they improve what they’re doing or how they’re acting if nobody confronts them about it? What if they don’t have the awareness to realize that anything is wrong in the first place? Make the difficult decision to tell them what they need to hear, even when it’s easier to tell them what they want to hear.