Typically in the north-east united states; A Diner is an eating establishment open 24 Hours a day - 7 Days a week where one can eat any meal - breakfast, lunch or dinner at any time of the day. Most Diners even serve alcoholic beverages during legal hours. Known for ample portions of a large variety of fresh food and and baking prepared on the premises. A great place for friends to meet and eat after a late night of drinking.
Christopher Specht

"allow it" means to just leave something alone, or don't worry about it. People in West London say this quite often.

the best place to be.

A prefabricated eating establishment noted for its long, thin floor plan, booth seating, and long counter top bar. While typically serving typical "american cuisine," such as burgers, coffee, and pancakes, diner menus may list items that reflect the region in which the diner conducts business, or the individuals that own it (such as Greeks).

Evil, Greek-owned establishment that employs anybody they can get, which usually means bums, crazy people, drug addicts, thieves, typical trash, etc. The occasional sad college student who just isn't prepared to be tossed into this frightening underworld of malakas. (Greek for asshole/jerkoff) Bosses are ALWAYS mean and/or demanding and/or unreasonable and/or borderline abusive. Tip your diner waiter/waitress VERY well; they aren't paid nearly enough to do this job, and it's ten times harder than any Applebees or Outback.