I've had lots of reasonable airline meals in economy or business class but none of them memorable. Equally forgettable are the bad ones. But one does stand out. It was 1993 or 94, Sao Paulo to Frankfurt and thence to London. The aircraft was a LH 747 Combi, late night departure from GRU. As soon as we were seated on the port side I could see there were problems on the ramp, pallets being unloaded, reloaded, some fairly frantic gesticulating down there.
The delay was around an hour and a half, explained by the flight deck as a need to get the W+B right. Thanks, that's always a good idea. And so dinner was served. Economy class this time. Steak and a salad of sorts. I think it was the side veg on the steak dish that had some sort of mould over it, from which several sprouts were trying to poke through the aluminium cover sheet. Same with my then girlfriend's meal, yecch.
To give LH the benefit of the doubt, back then I think they had an agreement with VASP for domestic ops and there may have been some VASP "help" in negotiating catering. VASP at the time were on the bones of their backsides financially and were desperately cutting corners. I returned via Rio and the domestic leg RIG-GRU was on a VASP 732 where the flight deck forgot or elected not to use flaps for take off. Took a long time, that, and I avoided LH and VASP forever after.