The type of game that when you recommend it, you have to clarify they need to play a few hours before they'll understand.
To me, many JRPGs have this problem. Xenoblade, Final Fantasy (14 especially), Tales, Kiseki, etc all take forever to get interesting.
Knights of the Old Republic II, the Witcher 1 (which itself is decent, but a long not-as-good preamble to the other two games), RPG's are bad for slow starts