Why do some people always deny what they have said?

Some people always deny what they have said. If there is any behavior, he always really doesn't remember what he said. Another person said to be proud. He doesn't think this sentence should mean that there is another person who is stronger, because he won't admit it until he says it.

Let's start with 1. 1, he probably really doesn't remember. He has a poor memory and forgets what he usually says, so he won't admit what he usually says, or he won't admit it if he has no impression.

In the second sentence, he thinks that even if he said such a thing, letting others know will have a certain image impact on himself, so in front of everyone, he generally won't admit that he said such a thing.

The third is that I said it, but I don't admit it is stronger. Usually, he is a strong person in life, so he won't admit what he said.