The definition of diner is a little vague, but by our reckoning any place that describes its menu as home cooking and serves pot roast, meat loaf and a smothered chopped steak is in the ballpark. You know, it's the sort of place you take grandma to on Mother's Day. The String Bean in Richardson has hit all those marks since '77 with its large menu of homestyle American favorites from burgers to soups to grilled salmon. It's unabashed comfort food without any fussy touches trying to turn it into something ... ugh ... "elevated." Fresh, hot, familiar, well-executed and it makes us think of Mom: that's elevated enough for us, and The String Bean in Richardson hits all those marks.