The Mask of Fu Manchu

Once you get past a knighted member of the British Secret Service (Lewis Stone) doesn't have a British accent, but Fu Manchu does. Another knighted Brit (Lawrence Grant) does have a British accent but his daughter (Karen Morely) does not. Somehow, Fu Manchu has people hiding in sarcophagi dressed as mummies in the British Museum, plus one guy who appears to be wearing a beret inside a sarcophagus, but disappears. Once you overlook all this, and a few other things, such as the British finding Genghis Khan's tomb in about the same amount of time that Sir Lionel Barton is kept under a constantly ringing bell, this is actually pretty entertaining.

You have Karloff as Fu Manchu who has all these elaborate methods of torture and killing people, and like in the Bond films, people tend to escape before dying. At one point, Karloff looks a bit like Carmen Miranda at the Carnival in Rio. Myrna Loy, as others have commented, seems to be a sadistic nymphomaniac, which for some people, is quite possibly the perfect mate.

Overlook all of the things that don't make a lot of sense and just enjoy!