No food is good or bad it depend on how we consume it.Sugar has gained a nasty reputation over the years largely because it is so often found in combination with high levels of fat in foods such as ice cream and pastries. Sugar is also a major source of "empty calories" with no real nutrient content.
Our bodies have been bombarded with sugar, with the average person eating their own body weight of the substance each year. This has happened far to quickly for us to adopt properly, and as a result, life-threatening disease such as diabetes, are becoming more and more popular. Aim to keep your intake to a minimum level, however this is hard to do, just look at the ingredients listing on most products. Aim to eliminate processed sugars from your diet, relying more on natural sweeteners such as honey, or fruits