My name is Sam, and my first visit to Buenos Aires was nearly 7 years ago, to visit my then girlfriend, who lived in the Zona Oeste (I have only recently found out that most porteños consider Morón to be one of the scariest places on Earth). A few hours after getting to her house, I had my first taste of mate, and when her mum saw me drinking it she burst out laughing and exclaimed 'Gaucho Sam!'
I'm not even in touch with her any more but that was the first of many warm and welcoming experiences I've had from people in this country, so it's stuck.