It's funny because technically Naruto's birthday didn't end with him losing an arm as the first time he fought sasuke (VOTE2) it was still his birthday. But chronologically he spent an entire day in a Taijutsu battle against sasuke so technically it was the day after his birthday he lost an arm...still a terrible birthday but look on the bright side he saved the world on his birthday.
Well he fought continuously for three days straight. Fought JJ madara with Sasuke, and sealed Kaguya with Sasuke (with a little help from plot, I mean Kakashi and Sakura). Then he stopped Sasuke from destroying himself in the darkness.
I'm sure he would do it all over-again to save his best friend. That's how much he cares .
He pretty much got to shine in front of all the villages and set into motion everything that resulted in their current state of peace, losing an arm seems trivial when you look at all he accomplished. He did more on his birthday than must ppl will do in their lifetime.