It is a question that will chime with most of us, our special memories stored away with their own musical accompaniment. There are the songs your parents played at home and murdered on Hogmanay, the records that filled the jukebox during those enlightening, early days of being granted access to the kaleidoscopic world of licensed premises and the records that kept you going as you bounced around some island or other somewhere in the Balearics.
For Darren McGregor, there is one tune that will always mark a special moment in his journey through this mortal coil, the moment he finally came to terms with the fact he had, in the wake of past rejection and two dreadful cruciate ligament injuries, made it to a club such as Rangers.
"It sunk in that I was a Rangers player when we were travelling up to Buckie in pre-season," he said. "I didn't know that before every game they put on Simply The Best before the bus pulls in to get everyone going. I was half-sleeping and woke up to the song. It was a surreal moment that will live with me. It was amazing.
"That was the moment I thought: 'I am a Rangers player now'. It is obviously a tradition the gaffer [Ally McCoist] has been through himself."
Tina Turner's heartfelt 1991 tribute to Scott Nisbet and Alexei Mikhailitchenko was not the kind of number McGregor associated naturally with football as a youngster, though. He was more likely to be found on the terraces of Easter Road, belting out one tribute or another to 'Le God', Franck Sauzee.
McGregor is a Leith boy. He, like everyone else with Hibee connections, worshipped at the feet of the Frenchman during his time in the green and white. Even now, the very mention of Sauzee's name almost causes the eyes to cloud over and the mind to drift back in time.
McGregor based his game on the former Marseille player when the 28-year-old defender started to make progress as a player in his own right. How strange his first competitive match in Rangers colours - a team essentially prevented from reaching a Champions League final by a goal from Sauzee in 1993 - should offer up the side he supported as a boy as opposition.
"When I was a kid growing up in Edinburgh, you had to pick your side," said McGregor. "I was from Leith, a Hibs area, so I grew up a Hibs fan and went to games regularly until I was about 12 or 13. It's tailed off a bit as I've got older, but I still always look out for the results.
"I looked up to Franck Sauzee and Russell Latapy. Sauzee obviously played in my position. His elegance and grace on the ball was something you don't see very often in Scottish football. I tried to base my game on Sauzee's, but I wouldn't say I got close to it. He was a great player and I'd never compare myself to him. I know my strengths and, if I can help these guys at Rangers out this season and next season, I'll be delighted."
McGregor, mind you, could be the subject of a few ditties of his own this evening when Alan Stubbs' side come calling in the first round of the Petrofac Training Cup. A number of his old friends are likely to be in the visiting section of Ibrox and he accepts they are unlikely to be singing his praises.
"I don't know how many [fans] Hibs are bringing through, but I'd imagine some of my pals will be in their end," he said. "I'll probably hear a few abusive shouts of 'McGregor' followed by four-letter words. I am more concerned, as a defender, about getting the clean sheet that will help us win."
It sounds strange to say it before the season has begun in earnest, but defeat in tonight's match could easily put the losing manager under a degree of early pressure. McCoist, preparing for his third full campaign in charge at Ibrox, has a poor record in cup competitions and losing at home to Hibs would not go down well among supporters still smarting over the failure to beat Raith Rovers in the final of this tournament last season.
It is a little different for Stubbs. He needs time to settle in at Easter Road and this oddly-named trophy for lower league clubs is hardly his main priority, but he will want to make a positive early impression.
"He is a great lad, just a solid man," said McCoist. "I have always got on well with Alan and I have real healthy respect for him as well. I think he will be a big success."
Of course, Glasgow is a real sporting centre right now, following the success of the Commonwealth Games. McCoist revelled in the stories of local residents going out of their way to welcome visitors from all corners of the world and joked that the return of football to centre stage, particularly given the never-ending wrangles at Rangers, might dampen a the optimism in the city.
"There is a feelgood factor about the whole place, no doubt," he said. "We'll bring it all back down to earth with a bang."