So do I, though I'm not sure why. Perhaps it's the composition or the implied serenity (though you'd think the animals would be chatty); and there are some beautiful sets, miniature, life size and living (though I'd never support the use of lions and tigers as mentioned in another thread).
Every year we go to the Grotto, a local Catholic sanctuary done up for the season with lights and festivities. The kids go right to the petting zoo, but we all enjoy the lights, the carollers, the performances in the chapel, and the living creche. And every year we sit through the somewhat out of place proselytizing puppet show and sip hot chocolate. It's the powdered kind, but it's still nice.