Back in the 90's I'd turn up at Rome for an Alitalia flight to say Pars or London to find it was Delayed - always - but they were delayed by so much you could always get on the "previous" flight which was delayed also - so I used to depart on time but on a different flight.
I once asked the check in crew why they didn't just change the flight numbers to put them all back on schedule and they were shocked, shocked.......