I looooved Calpis aka Calpico... I first had it in Japan and it was like nectar to me:
https://en.wikipedia.org/wiki/Calpis

I got some for Charlie the other day, and his eyes lit up and he loved it so much! It made me think about how taste associations are made when we're kids, and how now he'll always have memories of the first time he had this drink.

What beverages did you first come to love during childhood?