Why is that most parents can tell their children the truth and sometimes friends say what you wanna hear?

My dad isn't afraid to speak his mind and tell is what we NEED to hear either we like it or not. He can be brutally honest but at least he cares. He tells us what we DON'T wanna hear and not afraid to hurt our feelings. It sometimes offensive but for good reason. Sometimes my friends tell me what I wanna hear and that ends up bad sometimes. Most of the time I have to ask them if they REALLY mean it and be honest. My best friend is real with me which I love that. How come parents are mostly the people that can tell you the truth?