JUST SMILE AND SAY 'NO'
It can be annoying to be badgered by people touting their wares on the street or beach. But it's tough to earn a living. If a young woman proffers a menu for her restaurant, smile graciously and shake your head. If a man lugging his business on his back, tries to sell you a watch, kaftan or selfie stick, say "no" pleasantly. At a small cafe in Sulmona, in Italy, my companion shook his head when approached, reached in his pocket and gave the guy a euro for his trouble. Courteous, dignified and happiness on both sides.
DON'T BLAME THE NATIVES
If you have underestimated your travel time/ misunderstood timetables/ forgotten to validate your ticket or are just having a bad travel day, don't take it out on the locals. I witnessed an unpleasant altercation on a bus between a young man, who didn't have the right currency and the driver, who was quite reasonably explaining the rules. The young man threw a handful of coins in the driver's face and stormed off. The driver leaped from his seat to chase him. We remained captive until he gave up the chase.
LEARN A FEW WORDS
It is only common courtesy to learn how to say "hello", "goodbye", "please" and "thank you" in the language of the country you visit. If you haven't a phrasebook, ask an English-speaking person, "How do I say..?" and try to make a reasonable fist of the pronunciation.
DO NOT MOCK
Yes, I know trains always run on time in New Zealand, coffee is always strong and hot, and everyone speaks English. But you're not in Aotearoa now, Dr Ropata. Phrases such as, "God, things are slow here" or "Why can't they just..?" or "These people are so" suggest you should have stayed home. And, my personal bete noir: Do not ever use the word "done" in the same sentence as "travel" as in "I've done Italy, Greece, France or Peru." Or "I did the Galapagos last year." Places should not be ticked off like items on grocery lists. A passport is not a licence to be badly behaved.