The Giver #1 (From Mr.T's blog)

Even though I've already done a blog. I'll just do another one.

3. I think that the reason why The Giver thinks that people making their own decisions is frightening is because if they happen to make the wrong decision, the outcome would be unpredictable, and therefore, possible dangerous or cause chaos or harm. This is something that the community strives to avoid, upset feelings, or possible chaos.
If people start to make their own decisions then they would learn to become more independent, meaning they would start to listen to themselves more and less of others. However, even if it isn't the nature of the people to defy the rules of the community they might start to 'stand out' and become more then normal and actually start to make a difference in life, and that is what the elders fear most. People upsetting the balance of things.
One of the examples I have to support this is when The Giver discusses the possibility of people making their own decisions, immediately Jonas thinks this is absurd and completely out of the question because he fears bout if they make the wrong decision.