He has moved on and moved club but the day, the memory, the feelings of dejection still come up in conversation and haunt him still.
It was akin to a therapy session as he sat down to discuss Rangers' Scottish Cup quarter-final with Albion Rovers on Thursday morning. The 28-year-old didn't have to lie back and stare at the ceiling and there was no psychoanalysis of his words but the recollection of that day, April 12, 2008, will shape Foster's outlook tomorrow.
The defender was part of the Aberdeen side that, almost four years ago, blew their chance of a Scottish Cup final place, the 4-3 defeat by Queen of the South another unwanted and embarrassing milestone in a long line of misdemeanours in cup competitions for the Pittodrie club. Tomorrow, Foster will bid to reach that stage of the tournament once again when Ally McCoist's side host SPFL League 2 Rovers at Ibrox and the right-back needs no reminding of the consequences of a bad day at the office.
"That was a difficult one to take, all things considered," Foster said. "That was the year Rangers reached the final of the UEFA Cup and they were dead on their feet. We played them two weeks before the final in the league at Pittodrie and beat them 2-0. We would have fancied our chances. They were playing three games in three days, or whatever stupid schedule they were on. It was a sore one to take but that is what happens if you are not 100% and firing on all cylinders."
The odds on Rovers causing Foster more cup heartache are even greater than they were for the Doonhamers on that ill-fated afternoon at the National Stadium, even if the prospect of facing Rangers is somewhat less daunting for lower league clubs than it used to be as they face a side very much in transition. In theory, there should be no problems for McCoist's side as they look to set up another home tie in the last four and move one step closer to what would be their 34th, and surely most unexpected, success in Scotland's most prestigious knock-out competition.
With current favourites and League Cup finalists Aberdeen also facing lower-tier opposition in the shape of Championship Dumbarton, there could be a reunion for Foster and an eagerly anticipated resumption of a rivalry before the end of the season.
"Obviously, you don't want to get too far ahead of yourself," the former Pittodrie defender said, "but I have thought about the semi-final and I don't know whether I would rather play Aberdeen then or in the final itself. But let's just beat Albion Rovers first and then we can see what happens.
"You want to play against the best teams that you can because that will give you an idea about how good you are. We're a confident group of lads and we know we have a strong squad so it would be nice to face one of the teams who are up there in the Premiership. It would be a good gauge for us."
Rangers may be seeking the ultimate test of their current ability by squaring up to one of the handful of top-flight sides left in the competition, but it is the lowest ranked team in the last eight they have to see off first. James Ward's side have already made headlines and encapsulated the romance of the cup by beating Motherwell and Stenhousemuir to reach the quarter-finals. They head to Ibrox with everything to gain but Foster knows that, as individuals, a squad and a club, so do Rangers.
"It will be a tough game for us and they have already caused a few shocks and have done really well. We'll be well guarded against complacency," he said. "But the prospect of playing a semi-final at Ibrox is a massive incentive."