Cognitive therapy is a way of helping people to cope with stress and emotional problems.
The idea behind it is quite simple - the way we think about things affects how we feel emotionally. For example, if you wave to a friend on the opposite side of the street and they don't wave back to you, the way you think about your friend will affect how you feel about the situation. If you think your friend is avoiding you, you might feel sad or angry. On the other hand if you think they're are just absent-minded and didn't notice you, you might think it funny. So, our feelings are not just automatic reactions to events, they are shaped by the ideas that we have.