The Irish were eliminated at the group stage four years ago but the Munster star believes those memories will motivate the squad to improve their showing this time around in New Zealand.
"It is a totally different team from then," he said. "I'll be honest. It is the disappointments in sport that drive you on to excel and do well.
"I know anyone that was there and will be lucky enough to go on this one will not want to come back with the same feeling of regret.
"We were probably a bit under-cooked in terms of rugby. Sometimes it doesn't go your way but the majority of the time sport is fair."
Defeats against France and Scotland in their warm-up games also have no bearing on the upcoming tournament, according to the 32-year-old.
He said: "Winning creates a great environment around the squad and everyone's confidence is up and everyone wants to do well, but if you can't get the results it can be disappointing.
"But at the moment there is a bit of a balancing act. You want to get your set-pieces right and your patterns in attack and systems in defence and still get the result. There is the balance in winning ugly and getting everything right.
"There are areas to work on. We will know we will sharpen up. If we were three months into the season that would be a massive concern but, for some guys, this [Saturday's 19-12 loss to France in Bordeaux] was their first game back.
"We have to work on an awful lot. Everyone we have is well able to come in and perform to the best of their ability. The scrum went really well but the last scrum was disappointing.
"We are at the stage as a group of forwards that we can't afford one like that because it tars us with the same brush.
"Every scrum has to nearly represent the one before. You have to back them up and one bad scrum can ruin the day."
Ireland have a chance to avenge their defeat in France when the two nations clash again this weekend - something that appeals to O'Callaghan.
"The great thing about this warm-up, it's like a European Cup with the back-to-back matches because sometimes you have to wait ages to right the wrongs whereas if you can put in a massive performance again and really do well you don't have to have that year of suffering," he said.
"There is such a competitive environment within the squad, it is great at the moment. Everyone is looking just at the match at the weekend.
"At the moment everyone is really competing at everything and it is enjoyable and a great way to have it."
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