Explain the benefits of normalizing state and how optimistic updates work.

Normalize: instead of copying a person's name into 5 different places (and having to update 5 locations if the name changes, which is prone to errors), you record the name once in a directory and reference it by an index everywhere. Optimistic update: when you click "like," the red heart appears immediately without waiting for the server's confirmation — if the server reports an error, then the heart is removed.