A squad widely considered the finest in the nation's history has been undermined by inconsistency and has failed to realise its true potential beyond winning the Grand Slam in 2009.
The World Cup has proved an unhappy hunting ground, most notably four years ago when they exited the competition in the group stage following a torrid campaign.
Past experience has braced O'Gara for a tournament of potential extremes.
"Anything can happen at this World Cup and that's typical of us," he said.
"We can have a bleak campaign or a fantastic campaign. I suppose that's an upshot of our careers.
"That's what makes it hugely exciting - at this level anything is possible.
"There's a great mood in the camp and we are excited. It's a tough group but there are opportunities there as well.
"It's important to get off to a good start and try to build momentum."
For many of Ireland's biggest names - players like Brian O'Driscoll, Paul O'Connell and Ronan O'Gara - New Zealand will be their last chance to produce on the sport's greatest stage.
That knowledge has generated a sense of urgency and O'Gara, who has been a central figure in Irish rugby for over a decade, feels it as keenly as anyone.
"The fact this is my last World Cup is important," said the 34-year-old, who will be playing in the tournament for a third time.
"I've had a good career and made an impact at European level, but the World Cup is the elite level.
"It would be hugely fulfilling if I did have a role to play at world level and that's a goal of mine.
"Until you perform at a World Cup you shouldn't talk about it because you haven't done it.
"For years at Munster we were unlucky not to win the Heineken Cup. But when we did win it we earned respect.
"With Ireland we haven't earned that respect at world level. It's up to us to try and earn it."
On current form, Ireland look destined for a brief stay in New Zealand after losing all four of their warm-up internationals last month.
But spirits have clearly been raised by their arrival in the spectacular surroundings of Queenstown and O'Gara detects a change in mood.
"Our build up to the World Cup hasn't been the best, but the great thing about it is we have a chance to rectify things when it counts," he said.
"During the warm-up games we were mentally off-pitch. Since we've arrived here I've noticed a difference in attitude among the players.
"That will count for an awful lot and it will be interesting to see how we go in the first game.
"Maybe we viewed the warm-up games as trials while other countries saw them as full on Test matches.
"England were hurting from their defeat in March. They came out with a point to prove and proved it.
"There's no panic in the camp. We're not denying that we wanted to win those games but at this level you have to be at fever pitch.
"We weren't and it's important we are during the World Cup. That should bring out the best in us."
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