I can't tell you how many times I've been onstage in the middle of a performance and looked out into the audience and seen someone sleeping. Usually this person is older - that's a given. But some of the other details are a little more shocking. I would also say that more often than not this person is sitting alone. Now I would think if you were going to fall asleep at the theatre, it was because your significant other had dragged you to a performance that you really didn't want to attend on a day when you were too tired. That would make sense. But to be alone and asleep tells me that you really wanted to purchase a ticket for a good nap. Maybe they fell asleep because they didn't have their significant other to elbow them.
The more surprising thing is that these sleeps almost always tend to inhabit the front row. Sure, if you are observing from the stage, in many theatres you cannot catch those who are hiding in the back sleeping, but you're in the front row for goodness sakes!!! It's a great seat - you shouldn't be bored. AND the actors can see you; let alone most of the audience.
Before I go on any further, I must admit that I too have nodded off during shows. It's dark and usually warm. There are warm, relaxing colors from the lights and often there can be a soothing sound design or the even drone of the actors voices. All of this can be very hypnotizing. If I had a long day at work, it can be very easy to relax and let my eyelids fall. The only thing I have to say in my defense is that these are shows I usually have not paid for. And I hope that I wasn't snoring.
Yet it continues to puzzle me. Why would someone go and pay money (sometimes lots of money) just to take a nap. It's rude to your fellow audience members. It's disrespectful to the performers. And on top of it, you miss seeing the play.