America's influence on French and English youth

Mass culture and popular culture in the States have influenced the youth in France and the UK since 1980. But what exactly changed in the UK and France ? And in what way are both cultures influenced today ? The French are known for being a bit ignorant when it comes to the Americans, but does that count for the young frenchmen as well, or do they not listen to American music, eat at MacDonalds, watch American tv-shows just as much as any other European ? Specifically I looking at the 15-25-year-olds.

Anna