Worse still, they have seen their neighbours from the other side of the river Loughor in Ospreylia bring home the bacon too often for their liking.
Since the Scarlets claimed their only Celtic League time eight years ago, the Ospreys have won it four times.
For the 'Turks' of Llanelli, collective suffering in a rugby sense hardly comes much worse than that.
That their ancient local rivals found the sheer nerve to regain the trophy by outpointing Europe's premier team in their Dublin citadel will not have made the Scarlets feel any better.
The fact that the RaboDirect PRO12 trophy resides twelve miles down the road in Swansea, deservedly so after the Ospreys' epic Grand Final win over Leinster at the RDS last May will ensure the Scarlets do not lack for motivation.
Not for nothing does their new head coach, Simon Easterby, demand a top-four finish as 'the bare minimum'.
With that in mind, the opening weekend could hardly have gone better for the most westerly of the four Welsh regions.
It started on the Friday night with the Ospreys coming unstuck in Italy for the first time, paying the penalty against Benetton Treviso in every sense, losing Wales lock Ian Evans to the earliest of baths.
Twenty four hours later, the Scarlets had all five points in the bag at Leinster's expense.
Everyone needs a little luck here and there and the Sospans' came in the shape of a visiting team very different to the one responsible for routing Ulster at Twickenham in the European Cup final last May.
Leinster's three gold stars on their jersey, one for each winning European campaign, could not disguise the absence of stellar performers like Rob Kearney, Brian O'Driscoll, Jonny Sexton and Sean O'Brien to name but four.
Of the starting XV behind the most stylish victory in the history of the tournament, only two lined up for kick-off at Parc y Scarlets - Fijian full back Isa Nacewa and South African hooker Richardt Strauss.
The province's eleven centrally-contracted Ireland players were unavailable as they had been for the corresponding fixture last season, against the Ospreys in Swansea.
Injury having ruled out another seven, Leinster were forced to dig deep into their academy squad to complete their bench.
Team manager Guy Easterby could have been forgiven for wondering on arrival whether circumstances had contrived to overdo the brotherly love bit.
The Scarlets took advantage to run in tries galore, two apiece for wings Andy Fenby and George North and seven all told.
Leinster had not conceded that many in a league match for more than seven years on a night when Ian Madigan's late exercise in damage limitation spared them from a record defeat.
Madigan's reward for refusing to give up the ghost at least ensured that Leinster had the final word in losing 45-20.
By converting his own try, Sexton's deputy cut the losing deficit to 25 thereby sparing last season's beaten finalists the indignity of their biggest losing margin in the Celtic League - 31 points by the Scarlets at Stradey Park in April, 2004.
As home captain Rob McCusker put it: "The boys were on fire. We're looking for something to put in the trophy cabinet this season and this performance puts us on our way, even if Leinster were missing a few."
While a team can only beat what's put in front of them, the Scarlets know that Leinster's will be very different when they return to Llanelli on Heineken Cup business at the second round of the pool stage in late October.
By the time Easterby eased internationals like Matthew Rees, Jonathan Davies and Rhys Priestland into action via the bench, another Welsh region had racked up a bonus-point win.
Newport Gwent Dragons turned on the style to score four tries without reply and give the Zebras a punishing initiation into the harsher realities of life in the RaboDirect.
After watching the new Italian franchise lose 37-6, coach Alessandro Troncon will demand something better for their home baptism in Parma against Connacht on Friday night.
Treviso have shown them the way, their 12-6 win over the Ospreys an immediate indication of what it will take to make the semi-final play-offs next May.
With Italian and Irish teams breaking even, Wales managed three wins out of four.
In contrast, Scotland's two contenders lost their opening games - the Warriors going down to Ulster at Ravenhill, Edinburgh losing at home to Munster.
The Warriors, good enough to give Leinster a serious run for their money in last season's semi-final, break new ground against the Scarlets on Friday night, their first match at the Scotstoun Stadium.
Glasgow's enthusiastic hosting of the competition's official launch will have strengthened the Warriors' resolve to keep increasing their support after raising average RaboDirect PRO12 attendances last season to more than 4,000.
"We are up for the development of rugby in our city," councillor Archie Graham, chairman of Glasgow Life told captains, coaches and chief executives from the twelve clubs at the city's £74m Riverside transport museum on the banks of the Clyde.
"It is a very important sport for us, particularly in the run-up to our staging of the Commonwealth Games in 2014."
In his capacity as chairman of the RaboDirect PRO12, Andy Irvine anticipates another momentous ten-month campaign to emulate what he called 'a vintage season'.
"We had six teams challenging for the four play-off places and three countries represented in the semi-finals," he said.
"The final in Dublin was absolute box-office, a cracking crowd, cracking weather and a cracking match in the balance until the very end - a magnificent advertisement for our game."
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