Employees must choose those with spice skills, and since each coffee shop can only hire four employees, I personally suggest that you must keep four (actually three) employees with spice skills. Spice is a very rare game element (except diamonds). With spices, you can not only complete the task, but also get the money quickly (you can get a lot of gold coins by completing the customer's spice order, and you will probably cry if you make money only by ordinary drinks).