He predicts a bleak future of himself in 2015 living alone while Marshall and Lily are happy with a large family and Robin has married someone else, with the only constant being Barney will always be looking for a new girl.
When both of them wind up farting in front of each other, something Barney had been doing outside for some time, drawing the attention, and later obsession, of a neighbor across the street, inadvertently destroying his marriage, Quinn happily says that they are at least a real couple.
In an interview, show co-creator Craig Thomas revealed that in the flash-forward to 2015 that Barney's left ring finger is intentionally not shown.
He called it, "One of those little moments where you realize what a good actor Neil Patrick Harris is because he can somehow make hiding his left hand seem perfectly natural.
Club's Donna Bowman graded the episode a B+, stating that it had the show's "classic trope of flash-forwards and backs", mixed with fantasy predictions.