The diner is a national icon. Home to nighthawks, Seinfeldian banter, and orgasmic screaming, the interiors and exteriors of diners are a staple of Americana. Diners evoke memories of time spent with friends, usually as the coda of an evening on the town. Recollections of diners are less about the eggs, soup, and sandwiches eaten in them than the movies, concerts, and parties that preceded them.

And now after Beta Late Night, a show at Toad’s, or a date at the Criterion, hungry Yalies can head over to Diner 21, for the classic grub they crave and the warm fuzzy feeling of an American cultural tradition. Located on Temple Street directly across from the Criterion Cinemas, Diner 21 fulfills the role of diner well, but makes an annoying attempt to be something more — and fails.

The restaurant’s full menu of diner fare is competently prepared. The matzo ball soup ($3.95) is salty and oily (but in the way it’s meant to be) and the matzo itself is soft and flaky. The steak and cheese sandwich ($8.50) is a philly cheese steak on a hard roll, and a pretty good one at that. Sandwiches are all served with thick, starchy fries that err on the potatoey side of things and are a refreshing change in a city of thin, crunchy potato sticks.

Milkshakes ($3.95) are excellent, thick and sweet, and are the most attractively served item on the menu — covered in whipped cream, drizzled with chocolate syrup, and pocked with chocolate chips — but malts are not available, which is a cardinal sin in my book.

The BLT ($5.95), my diner benchmark, is a qualified success. A healthy amount of chewy bacon, leafy lettuce that isn’t a putrid yellow, and just the right amount of mayonnaise make this sandwich everything a BLT should be. Benchmark met. So Diner 21 meets the diner standard right?

Wrong. In a move indicative of the restaurant’s better-than-diner mentality, the menu claims the sandwich is served with “rosemary mayo.” No, it isn’t. Unless the chef was perfumed with rosemary when he made the stuff, rosemary hasn’t come anywhere near this mayonnaise. But it doesn’t need to. If I wanted a BLT made with pancetta, wild chickory, heirloom tomatoes, and a walnut-fennel mayonnaise foam, I wouldn’t have gone to a diner in the first place. Just toast the Wonder Bread! Bring me the Miracle Whip!

The fried dough ($2.90) exemplifies precisely what is wrong with Diner 21. Puzzlingly listed under appetizers, the dish comes in two varieties: cinnamon and sugar (reminiscent of churros) and marinara and parmesan (reminiscent of drunken college buttery food the day before the grocery order comes in). Neither variety tastes particularly good, and neither has any business being served in a diner. It’s best to stick to Diner 21’s more traditional greasy-spoon fare.

Service is sloppy at best, and we repeatedly had to flag down our waitress to place our order, to get silverware, and finally to get the check. But servers are friendly and the restaurant is brand new, so things may improve. But none of this would be a problem if the staff consisted of your standard haggard, jaded diner workers; but instead there’s a full platoon of twenty-something servers dressed in black who look like they should know what they’re doing but don’t. Diner 21 creates expectations and fails to live up to them, a failure that is made infinitely more frustrating because there was no need to create the expectations in the first place.

Diner 21 is a classic diner, and it isn’t. It features all the standard diner fare but also has a full bar. It’s open late but is also candlelit. It offers diner prices but also employs a hostess and takes reservations. The restaurant is a study in contradictions.

But don’t be fooled by Diner 21’s attempts to pretend to be something it isn’t. The restaurant provides good diner food at good diner prices. I just wish they’d scrap the delusions of grandeur and take pride in the marvelous institution that is The American Diner. They are a proud specimen of one of a relatively small list of culinary phenomena that are uniquely American. This should be enough.

But evidently, I’m the only one who feels this way: Diner 21 was packed on the night I visited, and as I looked around everyone was enjoying their meals. I was the only one waxing philosophic. Very well, Diner 21, do as you will, and so long as your upwardly-mobile aspirations don’t affect the food or the prices, I’ll quit complaining.