Is there an Italian equivalent for the phrase "shit happens"?

La merda succede

Which is, incidentally, a literal translation, with the exception of the article "la" meaning "the."

If you wanted to be a bit milder, you could say, "Cosi va il mondo," which more or less means "That's life."

As I am bilingual in the workplace, I would use terminology that is of more relaxed Italian. (That is, cussing, if I'm in private and in company of familiar people.) If I am around patrons, who might understand some Italian I would use "Così è la vita" (Such is life) and my facial expression would probably be a giveaway that it wasn't a good thing.

Most Italians, however, use the French "C'est la vie" in the same context. Then again, the people I mix with probably wouldn't be so polite.