Can anyone provide input on how to factor sugar content into making food choices? What is an acceptable amount of sugar in a day (for non-diabetics)?

I loosely follow Weight Watchers, which factors Fat/Carbs/Fiber/Protein into food choices. I can for the most part gauge appropriate values for these, but I wonder how the sugar content factors in. Obviously, I know high sugar is not good...but if the sugar content is high, and all the other values are reasonable, is the sugar counter-productive to all this?

THe best example I can use is Greek Yogurt. I have tried plain Greek Yogurt and just can't do it...even with some fresh fruit.
So, i have been trying to find a low sugar content Greek Yogurt, but that is tough. SOme of them have low fat, low carbs, high protein and little to no fiber (I get fiber in my other foods), but over 20g of sugar! What is the sugar doing to me in this situation?

Here is the one i have been eating lately (Voskos Greek Strawberry Yogurt, 6oz):
-0g fat
-18g Carbs
-12g Protein
-0g fiber
-15g Sugar