A great place for you to start in answering this question would be Chapter 16, which is where Jonas experiences Christmas and love thanks to a memory given to him by the Giver. As a result, his view on his life and the life enjoyed by his community changes significantly. After this point, he begins to dream and think about how he could act as an agent of change in this community, to try and bring things such as love back into their everyday life. Note what he says to Gabe at the end of this chapter:
Things could be different. I don't know how, but htere must be some way for things to be different. There could be colours.
What comes to preoccupy the mind of Jonas more and more as he receives more memories is how he can change the world around him to bring back things that have been dispensed with in his world. Jonas, as the novel continues, comes to judge his own life and to find many faults with it.