Coffee. After years of hating it and trying to keep people away from it, it finally got to me.
Tried this for the first time from kuya in Japantown like a month ago and I've been stocking up on them ever since.
It's cold, refreshing. Not bitter, neither overly sweet. No need to prepare it or clean it up, just toss it in the recycling bin.
Low maintenance + sweet + rush of energy = my kinda drink. It's cheap too, $1+ at your local Asian grocery store.