A bicyclist watched as two Irishmen were working in a park: one was digging holes and the other was immediately filling them in again.
“Tell me,” said the bicyclist, “What on earth are you two doing?”
“Well,” said the digger, “Usually, there are three of us. I dig, O’Hara plants the tree and Sean here fills in the hole. Today, O’Hara is away unwell, but that doesn’t mean Sean and I have to take the day off, now does it?”