I heard a woman struggling with her heavy suitcase and the small luggage spaces in double-deck TGVs uttering a loud "P*tain de m*rde" with a German accent - and it was glorious.
Useful trick in double-deck TGVs: if you have a big suitcase, go upstairs, then go left. The luggage spaces at the end of the other carriage are usually much less overloaded...