I find the best tactic in this situation is to let the other party exhaust themselves. You're never going to be heard, so just listen (actually listen, not pret

I find the best tactic in this situation is to let the other party exhaust themselves. You're never going to be heard, so just listen (actually listen, not pretend) until they've got whatever they want to say out, and then make a response that shows you've listened and tried to understand.