Carcassonne: The River
2001 / Tile placement board game mini expansion / 2+ players / Germany
Expanding Carcassonne by popping out further, slightly differentiated tiles feels even more decadent than buying card game booster packs. This mini starter takes care of itself by being included as standard in the base game nowadays, like a crafty heroin dealer giving you your first fix for free.
It's more variety for the map, and a nice teaser before the main feature, so I'll probably always include it, even if you're basically doing the same thing every time and the need for fussy restrictions to avoid tripping over itself is a foreboding preview of expansions to come.