Smith has long been one of those actors whose name in a film’s credits guarantees at least one performance worth watching. In the sleeper hit “The Best Exotic Marigold Hotel,” a group of British retirees travels to India with dreams of luxury, only to discover a run-down slum as its new home. While the cast is full of veteran charmers (Judi Dench, Bill Nighy, Tom Wilkinson), it’s Smith’s Muriel Donnelly who gets out enough one-liners for 10 films.