:) - yes, the "shut up and calculate" was a reference to quantum theory applied to GR, since people neglect to mention that GR doesn't explain what gravity actually is. And really, if you "shut up and calculate" using Einstein's Field Equations, you'll get results that largely align with observations, more so than Newton's equations, anyway. But there are observations that can't be explained by GR and there are simple thought experiments that can't be explained by GR. As I keep saying, we know GR is not the final word on gravity. That doesn't mean GR hasn't been incredibly useful - especially if you just "shut up and calculate!"