"I know where you're coming from". I hate that phrasing. It means, as you all know, that person A understands why person B would make his statement about something based on person B's properties or earlier experiences.
However, its literal meaning is too obvious for me to appreciate it. If person B is person A's twin, then it is obvious that person A knows where person B comes from. They are twins! They have lived all of their lives together and have the same parents! The phrase becomes a tautology.
This is something that has bothered me for a while. Does anyone agree that is an irritating phrase?