Iyla,
I used to make lemonade at home a long time ago sometimes and I used to be shocked that I needed around 3 teaspoons just to make it sweet enough, which is why I preferred store bought because then I am oblivious to the amount of teaspoons of sugar (unless I read the label). smack
The other thing is, some people dont have as many taste buds as others and therefore they require more of certain flavors than others in order to get a similar effect.