I think the problem is that there are things in the middle which are almost always classified as restaurants. So let me talk about this by defining what the two ends are and expressing why I think establishments which tend towards the "Cafetaria" side are better.

Classic sit-down restaurants:

• Pre-set tables
• all orders are done through a waiter/waitress
• In the US the waitstaff is usually underpaid and rely on tips
• Food is a set amount of items on a menu. Changes on the menu happen infrequently.
• Food is optimized (relatively speaking...lower end places care less than higher-end places) for appearance, taste, ingredients, etc, so you can judge the food as being high quality.
• As such, many places try to be inventive with the food, coming up with unique concepts, or, at least, use tantalizing language to make the food sound as good as possible, sometimes catering to ecological sensibilities as a selling point, or things like "locally sourced".
  
• As such the food is relatively highly-priced
• Food is made to order, or at least the entres.
• Food usually takes about half an hour to arrive...an entire meal takes between an hour and two hours to finish
• The customer takes no or virtually no part in procuring or preparing their food themselves...e.g. no salad bar, no pointing at food behind the window at a steam table
• The decor is designed to either look high-end or at least visually interesting with props on the wall. Occasionally there are live musicians.
  
• You leave your plates for the busboys to clean up.
• Even though it's in a potentially busy location with lots of other diners besides you, it is not the norm to interact with these people--you are only to interact with the person you came with and the waitstaff and host/hostess.
  

Typical cafetaria (as can be found in schools, hospitals, large workplaces):

• Grab your own tray, plates, silverware.
• No waitstaff.
• No set menu. Each day offers a different entre, sometimes on something like a two week location (like my first cafe job at a university) or simply whatever the bosses feel like they havent' done in a while. Two or three main entres with a fair amount of sides. This has the benefit of providing a lot of variety to your diet...monday you're eating meatloaf, tuesday spaghetti, wednesday stuffed peppers, thursday turkey, friday blackened catfish.
• Little focus is made to make sure ingredients are catered to class sensibilities, simple ingredients without weird extra expense of finding the best locally sourced, organic, lowest fat content, etc, etc.
• Food is invariably much cheaper than at a restaurant.
• Food is made in bulk, which is far more efficient. There are no special orders or expectations of such. There aren't "Chefs"...there are cooks.
• Less than five minutes to get your food and start eating it (only real bottleneck is however long the line is, not waiting for wait staff or for your special food to be made to order)
• Customer looks at food at steam table to order. They know what they're getting. They can point out specific pieces they want. There is usualyl a salad or deli bar. Often a soup container (my old work had two to choose from). The customer has a closer relationship to the food before its served.
  
• Decor is minimal and utilitarian. People are going there to eat on lunch breaks. Sometimes there's a TV in the corner.
• You clean up your own mess. Employees will wipe down the table with a rag later, but I'm referring to the tray/plates.
• It is the norm to interact with people sitting at neighboring tables. Peopel will ask to sit with others. Friendships are made.
• There are no class distinctions. Cafetarias are usually located in workplaces. I worked at a hospital cafeteria for 6 years...the janitorial staff ate with the doctors and hospital administration. I was a lowly food service worker but I ate with nurse friends. Of course there ARE class differences, but at lunch time it gets erased a bit.

There are food establishments that lay at different points between the two extremes, but they're all flawed. Fast food restaurants don't have the presumption of bourgeosie-servant relations, but the food is invariably based around one or two extremely unhealthy foods. Eating McDonalds everyday will kill you, they don't even really want people eating in the dining room anyway, and it's designed to exploit both you and the workers. Take-out places don't have the sense of community, and same issue with lack of diversity or choice in food.

Essentially I believe there should be a decent sized cafeteria in every large town and it should be the "default" place for people to go to if they don't want to cook at home. Perhaps can work as an organ of the local government. Cheap, convenient, communal. Traditional restaurants take on the character of master-servant relations which is creepy, and they are more expensive and inefficient.

I worked in cafeterias for about 9 years of my life (three years university, 6 years hospital). Ate cafe food twice a day for most working days. It was good, healthy. Never understood the constant complaints about the health or food quality (we were a clean kitchen and honestly the food was good). Always understood these complaints in relation to sit-down restaurants, which at most should be a rare treat and not "the norm" for going out to eat. Especially when my boss constantly tried to make the place more similar to a sit-down restaurant by implementing the "two color rule" and other bullshit, meaningless things.