Trundle through security, showing passport and boarding pass, remove coats, belts, shoes and the like (no problem with that, that's the rules and safety is rightly king nowadays), settle yourself for a cup of coffee at your departure gate and then decide to pay a quick visit to the loo before you board.

Problem is, to do that you have to enter one of those double-door (like the banks) security exits and when you get through it you're back outside the security-checked zone. To get back to your seat you have to queue again (with passport/boarding card), remove all that is requested of you and repeat the whole procedure. Bonkers, and especially annoying, I'd imagine, for families with young children in tow.