I think often, your favourite World Cup was the first you can properly remember and appreciate as a football fan.
I watched Euro 96, but was probably a bit too young to understand it and engage with it properly, so France 98 is the one for me. I know it likely wasn’t the best World Cup, but I just remember being wowed by the Dutch and the French, seeing some of the Brazilians for the first time and marvelling at how they were all so much better technically than the English side, who until then I’d childishly believed must surely have the best footballers on the planet.
Batistuta’s hat trick against Jamaica made me an overnight Fiorentina fan!