A surprise is going to your favorite Aunt's 60th birthday party with the rest of your family and waiting in the dark holding your breath until she shows up, hoping no one accidentally told her before she got there.
A surprise is your parents coming into your room and excitedly waking you up on Christmas morning to open gifts from Santa Claus, only for you to find your new best friend under the tree just waiting for you to come and play.
A surprise is not telling your parents how long you've been trying for, just so you can watch their faces when they finally open their new "World's Best Grandpa/Grandma" coffee cups and see your own excitement reflected back to you.
Getting to know someone better isn't a surprise. Spending time with them, and realizing that you're really hoping that you never have to truly say goodbye isn't a surprise. Missing them when you do finally have to leave and not knowing exactly when you get to hold them again, isn't a surprise either.
But falling for them absolutely was.