There are certain things you come to expect in a diner that you might not tolerate anywhere else. A true diner is apt to be one big smoking section, and there won't be anything on the menu (certainly not the chili cheese fries) that won't clog an artery. Carcinogens and cholesterol boosters aside, you get a lot at a diner that you can't get anywhere else. They're open around the clock, and they serve breakfast all the time. The waitresses treat you like a regular even if you aren't one, and just about anyone seated at the counter will gladly tell you his life story. The silver spoon of local greasy spoons, the Courtesy improves upon its East Coast forebears with Midwestern touches. The old-fashioned jukebox -- five plays for fifty cents! -- ranges from Bowie to Ozzy Osbourne but favors classic country. The coffee is diesel-grade -- great for washing down a towering meringue-topped piece of pie. This being St. Louis, most customers will opt for a slinger; other greasy goodnesses, from biscuits and gravy to chicken-fried steak sandwiches, round out the straightforward menu. And goshdarnit, there aren't many places, not even in St. Louis, where your cook will sing along to Ozzy's "Mama, I'm Coming Home" while she fries your eggs. We're giving the nod to the two-diner operation's Kingshighway flagship, but avail yourself of the second location (1121 Hampton Avenue; 314-644-2600) if you're in that neighborhood.