Gremlins, leprechauns -- call them what you like -- they all had it in for Lieutenant Johnny Dawson. He was the sort of bloke whose Sten would suddenly jam for no reason, or he'd be the one in a million who'd be issued with the grenade with a faulty fuse.
Yes, Johnny had a real JINX. He didn't like it, the top brass didn't like it and, most important, Johnny's men didn't like it. In fact if his luck didn't change soon he'd have a mutiny on his hands.