It is rude to interrupt someone you are conversing with.
Robert is eating lunch with one of his coworkers, whom is telling him about their week at work.
Robert wants to express his recent frustrations that he's experienced at work.
Robert waits for his coworker to vent their frustration, and then expresses his frustrations in kind.
Robert interupts his coworker in the middle of their story and starts complaining about his week.
Robert and his coworker form a close bond over their common frustration and grow to become best friends.
Rober's coworker scoffs at being interrupted, get's an early check and leaves the restaurant, leaving neither of them with someone to talk to.