I have been a regular customer on the TGV (HST high speed train) from Brussels Midi to Bordeaux St Jean on December 23 for years now.
That train generally is crowded to capacity, but for the very first time in years the windows were so dirty that it was literally impossible to see the landscape flashing by. People sitting by the windows used the stops to get out and clean part of the windows with paper handkerchiefs.
On the TGV travelling back from Bordeaux to Brussels four days later it was possible to see through the windows but the toilets were in a pitiful state. That is a far more common complaint than dirty windows, and it has to be said that people sometimes behave like pigs - with my apologies to the pigs. I always pity the women who have to sit down on those dirty thrones.
So customer care could be better, but the TGV remains a very fast and efficient way of transport for medium distances.