What happens if you only pray fard and no sunnah or nafl?

So the very first thing Allah will ask us about on the Day of Judgment is our Salah. We know this from the Hadith collection of Ahmad al-Tirmidhi. And Allah says that He will send an angel to look at our Sunnah prayers and our Nafl prayers to see if there's any deficiencies in our obligatory prayers to help make up for that. So it's really important to make sure whenever you have an opportunity, a few minutes to try and pray a Sunnah prayer or a Nafl prayer, if you're able to. We all make mistakes and those Sunnah prayers.