Secondly, I was using a "light alfredo" recipe, a bold step forward in oxymorons. Essentially, it substitutes yoghurt for whipped cream or half-and-half, no butter to speak of, and uses sauteed mushrooms to replace some of the lost moisture. Problem is, since there's no oil to hold everything together, you can't let the cheese melt, or it turns into curds. That, combined with my accidentally using non-fat yoghurt instead of the regular kind, made the sauce...not so saucy. And the sauce had a startling lack of garlic in it. Well...only one clove.
But, good flavor, the shrimp were pretty tasty, and I can see my way forward. First, puree some garlic and cook it into the yoghurt. Alfredo without garlic is a tragic thing.