Hmm. With interrupting there can be okay motivations for it I think. If they're being long-winded and you want to respond to a specific part of it, it can make sense to cut them off. (In a perfect world it shouldn't need to happen, but it's not always the interrupter's fault.)
So I think it depends. It could be that you're trying to force your message, but not all interruptions are created equal imo. It can also be that they're trying to take too much attention.