In Chapter 17 of The Giver, what changes have the memory brought about in Jonas?

This is a great chapter to consider this question because we are
told at the beginning of this chapter that an "unscheduled holiday" was declared. This should in
theory be a time of celebration and an opportunity to catch up with friends for Jonas, yet he
just discovers that his experiences only serve to isolate him. He is definitely a different boy.
The narrator tells us:

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Now, through the memories, he had seen oceans and
mountain lakes and streams that gurgled through woods; and now he saw the familiar wide river
beside the path differently. He saw all of the light and colour and history it contained and
carried in its slow-moving water; and he knew that there was an Elsewhere from which it came, and
an Elsewhere to which it was
going.

This knowledge and his
experience of "true" emotions really serve to separate Jonas from the rest of the community.
Jonas reflects that he experiences a new "depth of feeling" in his emotions, and yet he feels
frustrated by the so-called "emotions" that the members of the community say they
feel:

But Lily had not
felt anger, Jonas realised now. Shallow impatience and exasperation, that was all Lily had felt.
He knew that with certainty because now he knew what anger was. Now he had, in the memories,
experienced injustice and cruelty, and he had reacted with rage that welled up so passionately
inside him that the thought of discussing it calmly at the evening meal was
unthinkable.

Above all, when he goes
and tries to play with his former friends, such as Asher, and he is overwhelmed by the memories
of the war that their game re-enacts, Jonas realises how absolutely isolated he is in this new
community:

Jonas
trudged to the bench beside the Storehouse and sat down, overwhelmed with feelings of
loss. His childhood, his friendships, his carefree sense of security - all of these things seemed
to be slipping away.

It appears that
the memories Jonas is given are a poisoned chalice in many ways - through them he is able to feel
and experience life in a way that he has never been able to before, yet at the same time, they
make him irrevocably different and separate.