Say what you want but chit-chatting with people you know is far more fun and dynamical when everyone feels free to interrupt others. Part of that culture is of course learning to not let go, and fight back those interrupting you - refusing the interrupt request if you will.

Wait culture is IMHO more appropriate for larger groups of people and more formal settings, or some subjects that are very important to the one speaking, so interruption would be disrespectful.