„That’s the way the mop flops“
That is the way things happen.
Think in English
„That’s the way the mop flops“ : This is the way things happen; this is typical of a random pattern of events. (Contrived.) „Sorry to hear about that, but that’s the way the mop flops.“
Richard Spears, American Slang
„A philosophic comment on disaster. One can also say, ‘That’s how the grapefruit squirts’.”’ Well, the grapefruit var. never caught on in the UK and had, I gather, only the most ephemeral currency in the US. … ‘The phrase lent itself to variation, of course. A fairly common one in the 1950s—60s was “That’s the way the mop flops”; and a very local, short-lived, one in Hong Kong, 1962, after a particularly devastating typhoon, code-named Wanda! “That’s the way the typhoon wanders”.’
Eric Partridge, A Dictionary of Catch Phrases