How does The Giver challenge our society's attitudes in regards to the loss of individual freedom & the importance of memory and history for societies

The Giver shows us what could happen if we were willing to sacrifice personal freedom for the opportunity to never feel pain.  We tend to place a great deal of importance on "being happy" and we generally like to avoid things that are difficult or painful.  However, we see that giving up pain means that we also must give up exquisite joy; if we want to avoid rejection, then we cannot have preference.  In the attempt to regulate emotion to avoid pain, everything becomes moderate, and people must give up what is wonderful about life because they do not want to feel what is terrible.
Ultimately, the book shows us that the trade-off is just not worth it.  Yes, we will have to remember terrible things: genocide, war, the terrible things that human beings do to one another in the name of country, religion, race, and so on.  We will have to experience the pain of being spurned by someone we love or betrayed by someone we trusted.  But without the darkness, we cannot have the light.  Because we feel this pain, we also get to feel the joy of being truly loved, preferred above all others; we get to bask in the security of friends that are committed and loyal because they care for us; we get to make choices, and fail sometimes, and pick ourselves up and learn about the pride to be found in perseverance.  We might think that "being happy" is the most important thing, forgetting that we can only recognize a moment of real happiness because we know its opposite.  The Giver, therefore, challenges our attitudes about what a more perfect life would look like.