Whether they like to admit it or not, the current Northern Ireland players have a mental block about winning football matches, especially at Windsor Park.
It actually goes back to Nigel Worthington's time as boss when he was taking serious stick from disgruntled fans.
The negative energy coming from the stands affected the players and since then they have become anxious and on some occasions fearful, even when playing teams they should be beating with ease.
Michael O'Neill, yet to win as manager, acknowledged my assessment was correct after another disappointing result earlier this year. You need talent to succeed, but so much at the highest levels of sport is decided in the mind.
Watch how teams approach playing Manchester United this season with more positivity, simply because Sir Alex Ferguson is no longer in charge at Old Trafford.
With Fergie there, opposition sides were defeated before they stepped off the coach! And therein lies the problem facing the great Roger Federer.
Of course he is still a majestic, magnificent tennis player but on the back of his shock defeat to Sergiy Stakhovsky on wacky Wednesday at Wimbledon, Roger's aura is suddenly not so strong.
For the last decade you had to be among the game's elite to feel you had a glimmer of hope against Federer, who before his unexpected loss had reached 36 consecutive Grand Slam quarter-finals.
Now there will be lesser lights believing that if Stakhovsky can do it, so can I! The impossible will now be considered possible.
Should Federer (31) claim another Grand Slam, his 18th, it'll be his finest ever. He'll need all his renowned self belief to achieve it.