People tend to repeat their stories or anecdotes
Why do you think most people have a tendency to repeat the stories in their life?
I think there's no real reason for it.
It can be frustrating to hear someone repeat themself, but they may not even realize they are doing it.
Don't be a dick about it, you should listen to what they have to say.
You're right, we can all be better friends by listening to each other!