I (almost) always get an iced vanilla latte with whole milk from Starbucks.
Hard to mess up imo.
When I was in law school I used to make it every day for myself and it was always perfect.

Yesterday my Starbucks latte tasted crappy.
This morning when DH left to get us coffee I told him to try getting me a free latte since mine tasted like crap yesterday.

Success!

At $4+ it better taste perfect!