It is an expression of disappointment and distress. Greeks use it very often when something takes more time than they expected.
For example: Andreas: "When will we finally get the results?" Korina: "In three months". Andreas: "Α, καλά κρασιά! Till then, my hair will turn grey!".
Being kept in barrels and also prepared with high quality standards, all good wines require a long period of time in order to be ready, therefore, Greek people created this expression (καλά κρασιά = good wines) as a means to show that a case or a job will take a long time to be done. In the end, the meaning is negative because we want to express that we are in a hurry to do something quickly and we are disappointed by the fact that it will take so long.
So, do you feel the urge of using this expression in your life lately or is it the Greeks only?