"What a day" is a phrase that can be used in various contexts, including as a song title. There are several songs with this title on YouTube, including:

• "What a Day" by Tyler Shaw
• "What a Day" by Ben Howard
• "What a Day" by Matthew West
• "What a Day" by Faith No More
• "What a Day" by nobigdyl

Without additional context, it is unclear which specific "What a Day" song is being referred to.