Remember when Liverpool won everything there was to win on the football field?
Remember when the British Empire included half of Africa and the Indian subcontinent?
Remember when Heather Mills was Paul McCartney's loving new wife?
Exactly.
Things change.
And sporting clubs that have been at the top for years can find themselves on a downward slope pretty quickly.
Sometimes the money runs out, sometimes the management changes, sometimes things just go wrong almost without anyone noticing the bandwagon is about to career off the road.
The great Wigan dynasty of the early 1990s is probably the best example in rugby league, with the cherry and whites going from invincibility to vulnerability in the space of a few short years.
And I cannot help but feel that the wheel is turning at Bradford.
The Bulls are still one of the powerhouses of the English game, but they are certainly not the force they were in their pomp, when Brian Noble and Matthew Elliott presided over brutally efficient teams.
Last weekend's Challenge Cup defeat by a doggedly determined but terribly understrength Hull was the latest in a long line of setbacks.
The Iestyn Harris saga - which will surely be judged by history as one of the worst transfer decisions of all time - the loss of Noble and Stuart Fielden to Wigan, Jamie Peacock to Leeds and the departure of Kiwi strike pair Shontayne Hape and Lesley Vainikolo to the rah rahs, all signal a decline in Bradford fortunes that will take some arresting.
It is difficult not to feel a degree of sympathy for the fresh-faced Steve McNamara, who has the look of a coach trying to work with one hand tied behind his back.
And while the result on the field on Sunday was bad, it was the sight of the empty acres of terracing that spoke loudest.
A gate of just over 5,500 would be acceptable for some clubs.
For the Bulls, who used to drag in five-figure attendances on a regular basis, it looks suspiciously like an ongoing disaster, especially against a club like Hull, who have a significant travelling support despite their own recent troubles.
How many would have been there if Catalans or Quins had been on the menu?
Not many.
It would be a major surprise if Bradford's wage bill was calculated around gates like that, making it inevitable that the purse strings will continue to tighten.
And, in turn, that makes it more and more likely that McNamara is presiding over a dismantling of a trophy-winning team rather than the construction of a few one.