I arrived at the airport in Dublin at 4:30AM!!!! and only at that time i was informed that the flight will depart 8:30PM instead of 6:30AM due to a technical problem with the plane which was never departed from the initial destination in Ethiopia.
You did not check the flight status before heading the the airport? That was plain stupid. For longhaul flights from non-Hubs (where its pretty easy to guess where the plane is coming from) this is a very important thing to do.