Having one's nature deepened by tragedy

In Nightingale wood, Stella Gibbons writes

I must get a better job, thought Saxon, running lightly downstairs with his waisted jacket over one arm, but he did not think it dramatically or tragically; he thought it with impatient common sense. Neither he nor his mother were tragic people; tragedy overtook them, but it did not deepen their natures, because it found no answer therein. The long-drawn tragedy of his father's life had made Saxon, not bitter and humiliated, but self-respecting and ambitious.

I didn't entirely understand this any better than the Aristotelian view of tragedy that I came across before. For example, as George R. Noyes wrote of those who view Oedipus Tyrannus or Agamemnon

By the excitation of such lofty passions our own purely human emotions are purged of disturbing elements, are deepened and purified.

Personally, I could do without it, and when I see others engaged in frivolities or purely concerning themselves with superficialities, I envy them.