We've always had an inferiority complex with regards to them, as have most of their neighbours (the Germans especially). It is after all the part of Europe thats nearly always been the best part of Europe to live, with the most natural advantages and with the best style of life - good food, good wine, good views, good weather etc.
I think recently though, its the Eurotunnel that is to blame. Flying between Heathrow and CDG (or any French airport), or taking the ferry is pretty much swapping one standardized travel experience for another, but taking the train is basically you moving from a backwards country to a modern one. Its really obvious how cramped the Underground is (even a relatively modern line like the Victoria) after going on the RER, and as for the intercity services the difference between even the most modern trains here and the oldest TGV (never mind the Duplex) is vast. Everything about SNCF is demonstrably superior to here, even daft things like ticketing.