The Marks & Spencer's at London Victoria has a couple of manned tills and about a dozen self-checkout tills. There's always three or four clerks in the self-checkout area yelling "next please" when a self-checkout till empties.

That's their job now, see? Yelling "next please". That's just miserable and pathetic and I fully sympathise with the frustration at self-checkout proliferation (I guess I'm a bit of a neo-Luddite).

But that's not a justification for becoming a jerk oneself.