Play by the rules: theatre etiquette

Please take your seats ... Covent Garden's Theatre Royal awaits an audience. Photograph: David Levene

You've forked out for your mid-price West End seats and found that £25 has secured you a perch in row Q with a pillar obscuring half your view of the stage. You resign yourself to an evening spent with your neck bent at an unnatural angle. Then you spot some empty seats nearer the stage. A plan forms, but you can't make a move just yet. You need to wait until the last possible moment before claiming your prize, until you're certain those seats are truly vacant.

The solution is usually a dash forwards just as the lights are falling. But what if the seats belong to tardy types who dash in at the first scene break, demanding an awkward withdrawal? The dance of the empty seats is just one of the rituals of a night at the theatre and I doubt many people would object to such mild mischief provided it didn't impact on their own enjoyment.

There are a number of other rules of theatregoing, most of which boil down to a simple consideration of those around you. I believe it's unreasonable to expect complete silence and stillness from an audience. Part of the beauty of the theatre is the experience of sharing this moment with other people. Otherwise you might as well stay home and watch TV.

Fortunately most people seem to have got the hang of turning their phones off when entering the theatre and it's been a good while since I heard the trill of a ringtone during a performance (or an answered call). Checking and sending messages still seems to be a grey area; I often spot the telltale glow of a BlackBerry in the dark and hear the tap of a text being sent.

Talking is another matter. It seems unreasonable, undesirable even, to expect complete silence: gasps, exclamations or the occasional elucidation of a pivotal plot point are all valid responses. But again there is a line, one that only becomes obvious when people stray over it. I remember a theatregoer at a performance of Donkey's Years who was intent on explaining every single joke and reference to his wife, launching into each of these with: "Now you see, that was funny because ..."

Other bodily noises can be equally distracting. Everyone coughs from time to time (though West End audiences seem particularly susceptible) but, if you're about to expire from a coughing spasm, it seems only fair, for both your own sake and those around you, that you step outside. At the Barbican recently I sat next to a man with the loudest, bunged-up breathing. It was hugely off-putting, especially in the production's quieter moments, but I could hardly protest at someone's breathing.

So what sort of behaviour do you find unacceptable at the theatre? And what are your worst experiences?