I was taught and try to live by the motto

"It is better to be thought a fool, than to open your mouth and be known as one"

I interrupt my girlfriend sometimes, but lets me honest, if you dont interrupt a female at one point or another youll never say another word to them.

That is also one of my pet peeves mentioned above. Being on the phone with somebody and they start talking to somebody else they are with out of the blue. I would rather hang up than listen to their conversation. If I wanted other people to hear my conversation I would put it on speaker phone. Have the decency to ask me to hold on at least and answer the other persons question.