Man, this is why I suck at SC2 - I'm always forgetting something.
This game on Civ4, playing difficulty 4, I decide to shoot for cultural/tourism victory. I get 3 cities on fresh water for gardens, rush the writer/artist/musician guild, keep up enough military to keep the aggressive civs off my back (though honestly, this has to be the most pacifist game I've ever been in, everyone loves everyone). But I forget to finish exploring, and i meet the second continent quite late, wasting some of my early tourism generation.