There needs to be a way to pause the game if know you're not going to be able to play for some time (illness, traveling, work, etc.)
On the one hand, I love that the game keeps playing even when I'm not. For one thing, gameplay would otherwise be too slow.
On the other hand, in the earlier stages of the game [read: before you've achieved extra levels in farming], this can cause problems. Last weekend I went camping with family overnight; I checked on my villagers right up until we departed, and I was still more than 1500 points away from buying the next level of farming. When I returned, less than 48 hours later, well over half my population had died of starvation. This was very frustrating. There are plenty of times when I'll be gone from home longer than that short trip. It's really only a problem until you reach Level 3 Farming, but up until then you ought to be able to pause game play.