According to some statistics, And Then There Were None is bestselling Agatha Christie's all-time bestseller. It's been filmed more than once, perhaps the favorite adaptation until recently being the 1945 20th Century Fox version.
Some plays need to look as if they're being performed with absolutely no effort whatsoever. They must seem merely tossed off. That's the fun of them. Perhaps the most famous example is Private Lives, the jazzy romantic comedy Noel Coward wrote in 1930.