I used to work as a Barista.
I don't think I could ever be a barista and make all those different espresso-based drinks.
Yea it is a lot of memorization of adding different ingredients.
Although it may be relaxing to work in a coffeehouse where they serve hot coffee, tea, and sometimes food.
Yea there are lots of time for relaxing when you are not dealing with customers.
Actually all coffees are based on either espresso or coffee. There are different strengths and some have milk or cream and some don't. 
That is true, do you like cofee? You seem to know a lot about it.
 I like iced coffee that is brewed cold and has different flavors. 
That is probably the easiest to make out of all of the different types of drinks.
Coffee
Coffee is a brewed drink prepared from roasted coffee beans, the seeds of berries from certain "Coffea" species. The genus "Coffea" is native to tropical Africa (specifically having its origin in Ethiopia and Sudan) and Madagascar, the Comoros, Mauritius, and Réunion in the Indian Ocean. Coffee plants are now cultivated in over 70 countries, primarily in the equatorial regions of the Americas, Southeast Asia, Indian subcontinent, and Africa. The two most commonly grown are "C. arabica" and "C.
Barista
A barista (; ; from the Italian for "bartender") is a person, usually a coffeehouse employee, who prepares and serves espresso-based coffee drinks.
Etymology and inflection.
The word "barista" comes from Italian, where it means a male or female "bartender" who typically works behind a counter, serving hot drinks (such as espresso), cold alcoholic and non-alcoholic beverages, and snacks. The native plural in English is "baristas", while in Italian the plural