Art

The boardgame Carcassonne has been around long enough to have two editions.  For some strange reason, the publishers dramatically changed the art style between editions making them visually incompatible.  

This is a right pain because the game has many expansions and so sourcing the right artwork expansion for your copy of the base game can be a right pain.

Especially when rip-off merchants on eBay ask for completely silly money for the older, thus rarer, versions.  So, to muddle an analogy, it's cheaper to buy a new car than a light bulb for an Austin 7 - but I like the Austin 7 version...