In 1984, Rosa Mexicano opened its doors to teach New Yorkers that authentic Mexican cuisine did not mean chili-cheese burritos. It has since opened three other NYC locations, plus branches in Miami, Atlanta, and Washington, D.C. The formula? Guacamole prepared tableside, frozen pomegranate margaritas dispensed from a Slurpee machine, and upscale South-of-the-border cuisine. The original locale is a meandering series of rooms done in muted pastels — the pink mosaic bar matches the frozen margaritas — with white tablecloths and large plants. The dishes, from crabmeat enchiladas to beer-and-lemon-marinated short ribs with salsa ranchera, are mostly worth what some would consider a high price tag, and yes, the guac is tops. But this once-rich culinary outpost can sometimes feel a little rote, mainly because of the service, which can make you feel like you’re on an assembly line. Worse, the wait staff presses for more drink orders in a way that verges on harassment, and that seems less in the spirit of inspiring a tequila fiesta than procuring more pesos. Eating at the bar solves the problem, though it certainly doesn’t inspire lingering.