"What the -?'
-- Harry Potter
On the morning of Harry’s final departure from Privet Drive, Dudley leaves a cup of tea outside Harry’s bedroom. Harry steps on the cup, breaking it, having not realized it was there. At first, Harry believes that the cup was “Dudley’s idea of a clever booby trap”, but then, after speaking to Dudley, he realizes it was an act of kindness (DH3).
"There was a crunch of breaking china: he had trodden on a cup of cold tea that had been sitting on the floor outside his bedroom door" (DH2).
"It now dawned on Harry, however, that the cup of cold tea on which he had trodden that morning might not have been a booby trap at all" (DH3).