Miss Manners: I interrupted one conversation for another

Dear Miss Manners: During a casual conversation with a co-worker in the break room, another colleague entered in a hurry. We often share friendly banter about a sports team, and a significant event had occurred with the team the night before.

Wanting to make a quick comment to the second co-worker, I excused myself from the first. However, what I thought would be a brief exchange turned into a longer conversation about sports and unrelated work matters, inadvertently leaving the first co-worker out of the conversation.