"Get back on the horse"

My wife wants to give the aforementioned Italian restaurant another try! She thinks they were just having a bad day, and she said she liked her dinner just fine. "You just have to get back on the horse,'' she said. While I respect her compassion for the people who run the restaurant, I thought that "horse'' was an unfortunate word choice, considering the mystery beef that they piled on top of my gnocchi.