There is always one

Who will arrive at the ferry check-in desk hours before the ferry is due to leave.

Even before the check-in agent has arrived.
Even before the ferry has left the other side.
Even before the last coat of paint has gone on the HMS Sea-sickeness and it has been registered in Nassau, Bahamas.

Because one left one's point of origin with several hours of safety margin built in the estimated time to cover the 250 miles to the ferry terminal.
In case of a puncture.
Or mechanical problems.
Or adverse weather conditions.
Or a landslide in County Meath.
Or a volcanic eruption on the M4.
Or a spontaneous uprising of the Irish proletariat against the new budget (especially the over 70s)

This blip is dedicated to my mother, who has never missed a ferry.

Actually she has! Once she arrived so early for her Irish Ferry (St. Vomitus) from Rosslare to Cherbourg that she was checked-in by the agent who had boarded the passengers for a previous crossing (St Nauseatim to Pembroke).
He pointed her (and another 10 over-zealous travelers) to a rather obscure part of the car-park, somewhere between broken down lorries and a skip.
Needless to say that he forgot to inform his colleague who would arrive hours later to check-in the passengers for the St Vomitus. Everyone was boarded (except the precocious checkinators) and the ferry left without them.
If anyone is in possession of the CCTV footage from Rosslare harbour ferry carpark on 4 January 1998, I am willing to pay a small fortune to see my mother hopping up and down and waiving frantically for the ferry to come back (it didn't). :)