老天爷 is a culturally loaded term referring to the personified heaven in traditional Chinese folk religion — the supreme deity who oversees human affairs. You often hear it in exclamations like 我的老天爷！(Oh my goodness!) to show shock, frustration, or relief, similar to 'Good heavens!' in English. It's not the same as the Western concept of 'God' in a monotheistic sense; it's more like a generational Chinese cultural figure of ultimate authority.