Mattock submitted this

It can be useful, and sometimes important, to build big temples. If your temple is to small, all your undead creatures (ghosts and skeletons) will go there and become frenzied. They will not leave, but if you try to sacrifice any enemies, it will be attacked before it sinks, and the sacrifice will not be complete. Build more temple and the freanzied monsters go about their business.

Also, did you know that a big temple will keep your Reaper happy? If you have a large temple, ole' Horny is quite happy to live, train, and fight next to all your other monsters, there isn't even any need to keep him apart!

Dig a "Circle of Protection Good"?
(...but this isn't Magic the Gathering!)