The most special present was a preview of her own self-composed "Bittersweet and Crazy". She let fans hear a part of the song, and then sang the song herself live!  

SEE ALSO: "They're so good, this is what K-pop should be like," Girls' Generation's past live performance gains spotlight after 8 years

She also sang Ariana Grande's "Right Here" and Leona Lewis' "Bleeding Love", which you can check out below:

What do you think about her self-composed song?