Carl Rogers was a very smart man who studied how people think and feel, just like how you may feel happy or sad sometimes. He found out that when people go through tough times, like when they feel sad or scared, it helps if someone else listens to them and tries to understand how they feel.
Rogers believed that people need someone to talk to who will listen to them without judging or telling them what to do. This is called "unconditional positive regard." He also thought that people can grow and change and become the best version of themselves.
Think of it like this: Imagine you're really sad because someone was mean to you. If you talk to someone who says things like "That's silly, don't feel that way" or "Get over it," it won't make you feel better. But if you talk to someone who says things like "That must have hurt your feelings" or "I'm sorry you had to go through that," it might make you feel better.
Carl Rogers was like that second person. He believed that everyone deserves to be heard and understood, and that's really important.