Aside from Canada, this was our first time traveling to foreign countries where English is the primary language. It's a very different experience, and it allowed us the option to go on separate adventures.
No tipping! The service charge is either built into the price or added automatically. I've always been annoyed by tipping, even more so in Europe than at home, so this was a load off.
No sales tax on food! While this is the case in some US states, it's not always noticeable because the prices are down to the penny. It feels strangely civilized to see a $2 candy bar and be able to just pay for it with a $2 coin.
The 240-volt, type I electrical outlets are very nice. An electric kettle boils much faster at 2400 W than at 1800 W, and it explains why folks in British and Australian shows are always ready to make tea at a moment's notice! At least in hotels, there is typically a switch by each outlet so you can shut any plugged in devices completely off without unplugging them, and without a power strip. And although GFCI outlets do not appear to be a thing in AU & NZ yet, I feel safer knowing the plug can only go in one way, unlike the type C outlets in Europe. And unlike our polarized plugs, there's no fumbling to figure out which way is the correct way.
Downtown Sydney and Auckland look pretty much like any other big city, but downtown Melbourne is beautiful. I don't know what the reason is, but there don't seem to be any ugly buildings in Melbourne.
Contactless payments ("tap and go") are everywhere down under, except on public transit in Auckland and Melbourne. There we had to buy fare cards, with a substantial fee up front ($5-7). Sydney allowed us to just boop our credit cards (or phones) like we can for Omaha buses. For the convenience of occasional transit riders, this can't be beat. Unfortunately the rental bikes and scooters require custom smartphone apps that have access to all the sensors and data on your phone.
One thing the folks down under could learn from the US is to consistently make the dividing line between bi-directional traffic yellow rather than white. On two-lane streets, the center line is the same dashed white line as on a one-way street, making it unclear whether or not you should expect oncoming traffic in the right lane. In New Zealand many lanes are marked with directional arrows at the intersections, which we found very helpful as we were learning to drive on the left!
We were surprised by the lack of price gouging at concessions, for example cafes and gift shops in airports and museums. We're so resigned to paying higher prices in those places, it felt kind of weird to pay the same as at any corner cafe or shop.
New Zealand has a ban on single-use plastics, and everybody's making it work, including American companies. So when they say that a ban would put them out of business, that's a total lie.
Drip coffee is not the institution it is in the US. In a hotel you get packets of instant coffee and tea bags with your electric kettle. Everywhere else, it's espresso drinks, with "flat whites" and "tall blacks" particularly popular. In the commercial districts, you can find multiple baristas on every block, and not Starbucks either, independent cafes. While this was the case in Europe, last time we went (2016) most of the baristas had been replaced by automatic machines that can produce half a dozen (barista quality) drinks at the touch of a button. We didn't see those on this trip, and yet the prices were quite low compared to the US.
Locals were scandalized to learn that we came all that way for just two weeks, since they typically spend 4-6 weeks overseas. Jessie explained that if she took 4 weeks vacation she would lose her job, and then we would lose our health insurance. They were unsympathetic to this plight. In any case, we felt 2 weeks was sufficient time out of our lives!