Leo Cullen was angered by Leinster's defensive collapse in their Guinness PRO12 semi-final defeat to Scarlets last night.
The Blues head coach admitted that mistakes made throughout the team were "hard to explain" as the Welsh side ran in three tries in the opening 30 minutes on the way to a 27-15 win.
"Yeah definitely, yeah," replied Cullen when asked if he was fuming watching the errors made by his players that allowed Scarlets run in some easy tries.
"Making poor decisions on the edge and then we're obviously over-pushing, turning our shoulders and getting stepped on the inside as well. They were punishing through the middle as well.
"On both ends it's hard to explain. Scarlets didn't have a huge amount of possession but they really made us pay everytime.
"They were clinical in terms of, when we turned the ball over they struck unbelievably quickly against us so yes, a very disappointing defensive effort."
Cullen did not feel that the visitors gameplan offered anything unexpected but that Leinster's eagerness to get over the line left them open to being punished.
"Their threats were what we talked about yesterday. The disappointing thing is...for the most of this season, particularly at home, we played with a lot of attacking intent and sometimes that brings with it some risks.
"You come up against a team like Scarlets, if you're a little bit inaccurate, a little bit off, they make you pay and unfortunately that's what happened to us."
The Blues boss was left to rue missed opportunities to reach finals in the two big competitions this season but felt that the one missed at home felt worse.
"Particularly when you're at home at the RDS, the players have produced a lot of special moments over the course of our games here and it's almost like we've saved our worst home performance of the season until the last game.
"That's probably the most disappointing factor because players have produced a lot of really, really good days here and to turn out a performance like that, it's bitterly disappointing.
"But as I said, credit to Scarlets. They were so clinical with their chances, they took their chances well and they made life very, very difficult for us and that was with 14 men for 43 minutes of the game as well."