Made even worse when you realize that, at least in the original game, you'd get letters exactly like those from your in-game NPC mother... so that person's mom probably wasn't sending them letters at all. The game was.
Tearjerker restored: the in-game mom doesn't send letters or presents that often, and "her" letters tend to be all over the place as far as subject matter goes. There's undoubtedly some in-game letters mixed in there, but a lot of it is likely the real mother.
In Wild World, sometimes when visiting the cafe, you'll see Rover from the first game sitting at the counter. Hearing him fondly reminisce about traveling the world and meeting so many faces, and how he misses those days. It just sort of gave me a pang of nostalgia.