We've all got them. They have our best interests at heart - no, really - and think that overall we're doing a marvellous job, but they can't help noticing a few teensy things that might be done differently.
Then they systematically tear us apart, ending inevitably, as we stomp off thinking murderous thoughts, by saying that one of our worst failings is that we can't take criticism.
Oddly, while they consider themselves friends, we do not send them Christmas cards, although we can think of many other things to send them instead.
In the upside-down world of the Department for Education and Skills, this sort of relationship is considered healthy and constructive.
They now want to provide headteachers with critical friends, who will probably be other headteachers, to tell them what they are doing wrong in a constructive sort of way. Imagine.
There is the headteacher, dealing with the funding crisis while dealing with the results crisis while sorting out the truancy problem while erecting a tent where the woodwork room used to be before Maurice burnt it down, all the time knowing that later that day the critical friend will tell them exactly how they should have done it instead.
This plan is called by the DfES the Single Conversation. Headteachers will probably call it that, too, because there will only ever be one.
After that, the critical friend will be tied up in the woodwork tent and left there among all the sharp tools. With Maurice.
There is, however, a drawback to the plan: heads don't go in much for criticising each other. So in scenario two, as the entire school resources budget is blown on a packet of biscuits for the staff room, the teachers are helping the pupils to empathise with the victims of the Black Hole of Calcutta by locking them in 2B, and the parents are marching on the school carrying pitchforks, the critical friend will say "Couldn't be helped, old thing".
The DfES will then be happy with a job well done. And let's face it, the DfES should be damn good at its job: after all, it has thousands of critical friends of its own.