I can't do a good job of working or drinking if I try to do both at once. I've reworked several racing engines that were assembled by guys afflicted with various degrees of Budweiser Fever, and it's amazing how many mistakes they can make.
My "other job" is custom gunsmithing, and the same rules apply. If it goes bang, neither the assembly of the gun nor the ammo gets done if I've had even one beer. There's something about releasing 50,000 PSI of chamber pressure a few inches from my nose that demands my undivided attention!
Jerry