Success of provinces shows that parish mentality vital to growth of Irish rugby
Johnny Sexton summed it up best when he spoke about the pain he felt losing a Champions Cup semi-final - this is new territory for him and will take a while to heal.
When you hit your thirties as a professional rugby player you lament lost opportunities because you know they may not present themselves again.
The average age of this Leinster squad is low but that does not necessarily mean that success will happen regularly in the rest of their careers.
There is no doubt that after the last couple of European games and indeed the Guinness PRO12, there is definitely a Champions Cup in this squad of players but, as always, this is easier said than done.
The overall performance against Clermont draws up a lot of analogies and clichés - the one that got away and one Leinster can learn from etc and across all boards nobody can disagree.
However, as gallant as the performance was in the second half, the first-half mistakes were catastrophic in play-off rugby.
Two simple rules from the ages: you cannot play with 14 men and you cannot expect to win when your set-pieces are failing.
Isa Nacewa has got a little narky in his old age. His contribution to the club will unlikely be matched but every Leinster man, woman and child agonisingly counted down the 10 minutes he spent in the sin bin. As he sat there helpless, the scoreboard ascended in Clermont's favour. It was stupid mistake from an experienced player and captain, which was of course against character.
The lineout has been a bone of contention in the past few years and I have no doubts the stats and numbers are wonderful as you look back on the season but at crucial times in crucial games it regularly fails.
To lose three of your own lineouts in a row puts a team under huge pressure and suddenly attack turns into defence. Vital yardage is also lost. Furthermore, if there wasn't enough pressure on the set-pieces as it is the next lineout becomes even more important. Fundamentally then the situation spirals out of control.
Ironically, Leo Cullen, one of Ireland's greatest ever lineout experts, was sitting in the coaching box watching this unfold .
In the first half the less experienced players in the team waited for things to happen instead of making them happen like the second half. Rhys Ruddock was outstanding from start to finish and as the game progressed his colleagues caught up with him.
He is a real big-game player and rises to the occasion - in case anyone forgets this, write it down for next season.
Robbie Henshaw, Sexton, the rest of the back-row and, of course, Garry Ringrose more than shone in a show of great mental resolve and character.
The mental test is not over yet though. A five-day turnaround against a fresh Glasgow side and a switch of competitions.
Glasgow have lost some momentum but will prove adequate opposition to reignite Leinster's quest for silverware.
Apart from the resurgence of Cullen's squad, the value also of the Pro12 has increased. Leinster at the top and Munster in second proves that this competition is a springboard for European and international success.
There is little doubt that no other European side in a semi-final play-off could have gone 15 points down with 14 men and recovered the way Leinster did.
That alone proves the future is bright and the long trip home will be remembered at crunch stages of games next season.
The success of Munster and Leinster this year will lift Connacht and Ulster and the organisers of the Champions Cup have the Irish fans to thank for filling the stadia in the quarter- and semi-finals which has not happened to date in its new guise.
International and provincial rugby becomes more of a business every season but once again Irish provinces show that the parish mentality and belief in the jersey can beat the money men of England and France.
The rest of Europe should take note.