From guys waving frantically at their oblivious friend to the "could you scoot over?" people, CollegeHumor has put together a video that provides a fairly comprehensive list of the inhabitants and uncomfortable situations of the before-the-film theater experience for you to nod in knowing agreement to. Enjoy. Sorry, no handjobs; that's more of an after-the-lights-fade thing.
My big fear is always the really old person mistakenly entering a complicated film. When the elderly don't understand something, they are not hesitant to ask their neighbor about it.