Life is full of constant interruptions. I've been interrupted by a needy cat, multiple buzzing noises from my phone and the sound of someone edging their yard in just the past few minutes. But I find verbal interruptions the most irritating, especially when it's the same person doing it repeatedly. The implication is that what the interrupter has to say is far more important than what I was saying. Yet, even though interrupting is considered rude, we all do it.
One reason is that sometimes interrupting is necessary. If you have an important question to ask during a presentation that won't be relevant if you wait until the end, sometimes getting the speaker's attention is acceptable. You just have to do it politely [source: LaFrance].
But like many bad habits, interrupting can also be about power -- who is allowed to speak and who isn't. You might not hesitate to interrupt a subordinate at work, but you would never interrupt your own boss. No matter what the relationship is, though, it's usually still better to wait until the other person finishes speaking. Try to focus on what she's saying and formulate a thoughtful response. If you feel the urge to interrupt, ask yourself what would happen if you waited. (Probably, nothing.) You might even take notes if you're afraid that you'll forget what you're going to say later.