I'm embarrassed to say that I used to do this far too often, and I intended it as some sort of connective tissue with the person I talked to. And then I began to realize that it irritated me when others did it to me...
I'm aware that some sharing of common experiences can be connective, too. But the constant use of another person's experiences as a springboard for your own is dismissive, and it feels that way. I'm with you, Klara Jane: it's an irritant!
Good luck with moving toward better communication.