Buffy has done some amazing things over the years.
Taken down an actual god. Yeah, she had to die to do it, but she still won.
Sent the First Evil packing with its virtual tail between its virtual legs.
Saved the world so many times she's lost count.
She squeezes Spike's hand hard enough that she hears his bones crack. The pain is unlike any she's ever experienced.
"Slayer, you can't quit on me now."
Exhausted, she gives her last bit of effort.
"The baby's head is crowning!"
A minute later it's over, the most amazing thing she's ever done.