The Authenticity Dilemma

What do we mean when we say we want an authentic experience abroad? 

Authenticity in travel has confused me for as long as it has intrigued me, and this conversation with this tuk-tuk driver motivated me to seek out answers to seemingly impossible questions: Am I ever able to have a truly authentic experience, or to experience life as the locals do, while I am here? Is that an ethical goal? Is my presence here even ethical? Shouldn’t I just be on my couch at home reading about this place instead of contaminating it with my western ideas and ideals?