Choosing your seat in an sort of theatre (Lecture, Movie, Operating ("Who are you?! Get that popcorn out of here!")) is always a nightmare. You come in, and a quick scan of the surroundings give you a pretty good idea of where to sit.
You don't want to over-commit. Too close to the front, and you're practically involved. Too far back, and you won't be able to see. If you're in a theatre to watch a play (Or other theatre-based activities, perhaps you're into contemporary dance. It's really up to you) you'll mill around half-heartedly somewhere in the middle, being forced into one row by a decisive family member or perhaps a particularly impatient passer-by, desperately trying to get to a seat before he is left to sit at the front, isolated and alone, like a dog left out in the rain, his eyes displaying unknowing disappointment. "What did I do wrong?" he seems to say. "What did I do to justify this torment?".
Or, worse, you could sit too far back. A nightmarish scenario. Perhaps the passer-by himself committed early to a row and this forced you back a row or two whilst you made up your mind. It's a scenario I can scarcely begin to imagine before shuddering in horror. All of a sudden you're struggling to see, and if you're in a class of any sort, the lecturer consigns you to the scrapheap of slacking failures.
So you've gone in and eventually sat down. You think it's a decent seat, perhaps 4 rows back. All of a sudden, from the other end (This is a dual-open row, a hasty decision to sit there can leave a man feeling overcome with remorse merely seconds later) comes a person whom it is unlikeable to sit next to. Perhaps he has a particularly pungent body odour. Perhaps he insists on using his phone. Perhaps he talks to you. I can only speculate on these matters.
Being as you are a person of class, it's too late to back out without being rude. The second you step into that row you are committed to a brief fling of a relationship with whomever you end up paired next to.
Speaking from personal experience, I was seated next to what I like to affectionately term a Querier, and in my less fond moments, describe as a shaved gibbon foolishly let into a class.
You know the type, of course, and it seems pointless and needless of me to elaborate, but for those of us who have not had the honour and privilege of having someone relentlessly interrupt a riveting lecture (In my particular example, Relativity and the effects it has. Your lectures may vary) with their self-involved "Look how clever I am" questions. They're mainly rhetorical, with an overarching theme of "I'm really trying hard and I'm clever!" which is almost specifically designed to make me go back to my flat with a sense of burning passion to undeniably thump him in the final exams, to serve him right for being such a brown-noser.
As it was, of course, the Querier usually sits at the front, so I felt relatively safe sitting as far away as possible from his usual location as I physically could without being dreadfully rude and sitting like a leper in the corner. Sadly, however, he sat next to me, and, being as I was fully-connected with the seat, to back out at such a late stage would have been nothing short of a social faux pas on a par with eating with your fork in your right hand. Perhaps even worse, as if such a thing is imaginable.
Then, as if such a thing would have even crossed your mind, he spent the majority of the lecture pretending he had friends by texting. "Dear Mum...", I imagine they all begin. To relieve the tedium of texting his mum with updates, he asked pointless questions (Largely about the Doppler effect with regard to light. The excitement got to me too.) and shuffled awkwardly in his seat, frustrating me to a degree.
However, the final coup de grace came only at the end of the lecture, when, whilst packing up, he asked me to move to allow him past. "Excuse me, could I please get out?" was precisely what he did not say. "Man," he opened, and my teeth ground gently. "Could I just squeeze past?" he muttered as his final pointless question. It was only with the greatest of self-restraint I found myself letting him past instead of shouting "You sat next to ME, you horrendous man." at him.
Anyways, I hope this tale of woe guides you in your seat choices. I know for certain I shan't risk it, and I hope you can learn from my experiences.