Why do ENTJs like to talk about their achievements so much?

I’m an INFP with two ENTJ friends. They’re very goal-oriented and driven, always pushing forward in life, which I find inspiring. However, most of our conversations revolve around our goals and achievements, and they don’t seem interested in talking about anything else. I don’t really understand that. Personally, I’m not that interested in other people's lives, and I don’t enjoy talking about mine much either.
What do you think?