this is true, everybody has bad days in welding.
The difference that seperates the good and bad welders is your ability to blame it on something else. "Musta been the machines, rod, filler, flux,fit up, shielding gas, inspector, NDT tech, base metal, grinding wheels, heat treater, fitter, tacker, design engineer. Heaven knows I did everything I could and I still have porosity and crater cracks..."