During the week, I work as a barista! I love making espresso-based coffee drinks!
I love coffee!  Was it hard to learn?
It was a little tricky learning how to operate the espresso machine! It can be quite finicky! 
When did the profession of Baristas come about?
I'm pretty sure it's an old profession. The word barista is an Italian word that translates to bartender. Most Italian baristas serve hot drinks, cold alcoholic drinks and snacks. I'm not so sure when the term came to the US.
Interesting, I didn't know that?  Is it customary to tip a barista?
Yes, it is. Especially if your barista prepares a difficult latte art, cappuccino or latte. Those are a little more complicated to make than a standard drip coffee.
What is latte art?
Latte art
Latte art is a method of preparing coffee created by pouring microfoam into a shot of espresso and resulting in a pattern or design on the surface of the latte. It can also be created or embellished by simply "drawing" in the top layer of foam. Latte art is particularly difficult to create consistently, due to the demanding conditions required of both the espresso shot and milk. This, in turn, is limited by the experience of the barista and quality of the espresso machine. The pour itself,
button operation to an involved manual process. Espresso is a notoriously finicky beverage, and good manual espresso making is considered a skilled task. Further, preparation of other beverages, particularly milk-based drinks such as cappuccinos and lattes, but also non-espresso coffee such as drip or press pot, requires additional work and skill for effective frothing, pouring and most often latte art.
The barista usually has been trained to operate the machine and to prepare the coffee based on the guidelines of the roaster or shop owner,