cold coffee may be good, and instant coffee may be tasty? but cold, instant coffee is neither good or tasty.
Trying to get a simple cup of iced coffee at a Charbucks or S(econd) B(est) C(offee) is difficult, both have some vile concoction they sell as iced coffee that has been steeped overnight-it tastes horribly carmelized and syrupy.
Asking simply for coffee over ice results typically results in a cup of lukewarm coffee because many corporate baristas don't know how to properly ice coffee -I've pulled a few shots in my time, and it's astonishing how stupid most baristas come across nowadays, maybe it's because they deal with coffee drinking ignoramusses that have no idea how to order espresso.