Also known as a torture chamber. It is a place where hapless college students are sent to consume henious, toxic concotcions that are labeled as "food". Actually a conspiracy to cheat college students out of their money before the "food" kills them.
There are other kinds of cafeterias than the college cafeteria:

Each cafeteria, with the possible exception of the restaurant cafeteria, inevitably has at least one cafeteria lady. The kind of person that really doesn't look good in a hair net. The kind of person that you really don't want handling something you're about to put in your mouth.
Once you've been standing in line long enough, your tray will eventually accumulate a collection of substances which might, at some point in the past, have actually resembled something edible. Now, however, they look to you like chatty noders look to EDB.
Whether or not you had any choice as to which noxious substances in particular made the journey to your plate is dependant on the type of cafeteria in which you find yourself. School cafeterias are notorious for having a choice only of whether you get regular milk or chocolate milk. Everything else is unceremoniously dumped onto your tray. Sometimes, you don't even get a choice as to whether or not you actually ingest the stuff - they actually made us take one bite of everything before we could leave in my first grade cafeteria. I cleverly got around this by swirling my fork in each of the shapeless masses on my tray - the volume difference of a single 6-year-old bite of food out of an entire serving is kind of hard to spot, so I managed to escape to the playground with a minimum of gastrointestinal disturbance.
Things to watch out for in any non-restaurant cafeteria: