But what happens when virtually everyone who serves you turns out to be one of your students?
You could try the direct approach and say something like: "Hello Winona, fancy meeting you in a place like this." But be careful, because Winona might not be the shrinking violet she appears to be in your classroom. "Wife got you busy decorating again?" could be her curt rejoinder, and in a very loud voice.
Coming up with a pithy remark to restore the balance of the exchange can prove difficult while you are fumbling for the shop loyalty card.
It goes without saying that a trip to the chemist is fraught with dangers. Be careful, also, what you load onto the conveyor belt at the supermarket. An innocent visit to pick up some toilet rolls, a bottle of Albanian Merlot and a packet of rubber gloves could lead to the uncertainty of intimate betrayal from Natasha-How-May-I-Help-You when you hand back another one of her lacklustre essays on Monday morning.
And when you are celebrating the 50th birthday of one of your colleagues from the sports department by singing karaoke on the tables of an Italian restaurant you realise that the waiter taking Polaroids is none other Tony from your English class. It is even worse when you remember the next hung-over morning that Tony is a leading light in the college yearbook team. Oh well, you will just have to laugh off the embarrassment of being on the front cover again this year.
"You live too close to the bloody college, that's your trouble, says y mate Colin from maths. "It's no coincidence that the principal lives 60 miles away. I bet he doesn't bump into the vice-chair of the student council when he calls into the garage to fill up his Volvo."
Once you realise and accept that every minor or major life purchase comes accompanied by the fresh-faced smile of a student then shopping is, well, predictable. For certain items you could resort to mail-order, making the effort to ensure that you are mailing to a town many miles away.
Inviting people into your home to lay carpets or fix taps or erect aerials can also take on a coincidental twist. It turned out that the man measuring up my windows for some double-glazing was the parent of one of my students.
"So you're Barry's Dad?"
"Is he behaving himself? he barked.
I should have spotted the family likeness sooner, especially when Barry's Dad arrived an hour late, didn't have a pen that worked and then asked me if he could use my toilet. He didn't reappear for 20 minutes, by which time the tea he demanded had begun to stew in the pot.
At least I will never be anonymous. I should bask in the recognition that these encounters bring. I should acknowledge those knowing winks from my students as a form of flattery. We have a mutual trust. I hope.
If I want to buy a copy of Hello in the newsagent, where Rapinder works, then I should not hang around until she has slipped out the back before making my purchase.
And I should not be unable to cope when leaving the barber's as Carl looks up from his broom handle and asks me whether I will be needing anything for the weekend.
I just need to be careful what I say.
Donald Hiscock is a college lecturer