This is from my personal experience. It is like anything new or different. Stevia is not sugar, this must be stressed. Like all other sweet substitutes, yes they have a sweet taste, but there are a combination of after-tastes that turns many off.
Case in point. I know of some people that are so addicted to the taste, yes the taste is addictive, and have gained so much weight that they are using sugar substitutes to control their weight and diabetes. This one person that I know was spooning the substitute into their coffee. Well the coffee became bitter because of the interaction of the substitute and the coffee.
When it comes to substitutes there is a limit. There is even a limit to sugar itself before the body reacts to it i.e. weight gain, ADD, ADHD, diabetes.
Stevia like all things is an acquired taste. I personally do not taste sweet so therefore items that are heavily ladened with sugar and honey can be eaten with out me saying 'Ohh that is too sweet'. I personally use stevia to have that sweet taste in my mouth, yes I can taste this sweet. I like it because the variety that I use has very little after-taste and the taste is lasting. Among other benefits the taste significantly moderates my intake of sugar.
As with all things another example. When it comes to milk, I can not stand to drink cow's milk, but I like soya and goat or sheeps milk in that order. After drinking soya milk I have developed a preference. The same is true for stevia, it is an acquired taste.