Why is it that when you like someone who will never like you

Why
is it that when you like someone
who will never like you back,
you still don’t lose hope on them?
That there’s this hope inside that makes you
hold on a little longer on that person.
Why is it that when you know that
the only relationship you can establish with them
is friendship,
there’s still a voice inside you that whispers,
“Keep trying”?