How does the quote in Our Town, "You've got to love life to have life, and you've got to have life to love life," emphasize Wilder's theme?

In Act 3, Emily
dies in childbirth and joins the dead at the cemetery. There, she discovers what the others who
have passed before her already know: you can't go back into your old life again and expect it to
be the same. She also discovers that the living are "shut up in little boxes," that
is, they have a narrow perspective compared to the omniscient view held by the dead
characters.

"You've got to love life to have life" is a quote that
encapsulates this lesson learned by Emily and others -- appreciate life while you have it;
otherwise you die with regrets.