Sounds like you had great time in Australia.
1) Did you find the people there to be friendlier than the people in Canada and the United States?
2) What would you recommend for me to do/see when I go back to Australia one day?
My answers:
1.) People in Melbourne and Tasmania are the friendliest and most helpful people that I had ever met. People in Sydney are friendly.
2.) There are alot of things that you might want to see in Australia. I openly admit that two weeks vacation is not enough.
Sydney
Going to Manly on a ferry. Make sure that you leave Sydney after 2 p.m. and return to Sydney after 6:30 p.m. during their wintertime. You can take pictures and video clips of beautiful glowing Sydney downtown while the ferry is returning there.
Sydney Tower
Opera House
Harbour Bridge
Featherdale Park
Olympic Park
Darling Harbour
Tarango Park Zoo
Chinatown
The Rocks
Melbourne
Downtown Melbourne - the best of the bestest in the world IMHO! Chinatown, art galleries, skyscrapers and so on are there.
Victoria School for the Deaf - the oldest and existing school for the Deaf in Australia
Old Mebourne Gaol (Jail) - where Australia's the most famous and legendary vriminal Ned Kelly was imprisoned and hanged for his crimes
Eureka Tower - Wow! You can go up to 88th Floor where the observation deck is. What's more is they have a cool feature called the Edge where the glass cube with several people inside is slided out and in of the building for looking anywhere.
Rod Laver Stadium and surrounding areas - it is where the Australian Tennis Open is played. It is even adjacent to about 36 tennis courts!
MCG - it is the most well known sports stadium where the cricket and Aussie Rule Football games are played. The Aussie Rule Football field is about
two times and a half bigger than NFL football field.

My friend, his two kids and I went to AFL game at Ethiad Stadium and it was so interesting.
The Shrine - It is a place to honour Australia's dead soldiers from wars that they took part in. It is one of the most beautiful and well-respected buildings in speaking of respecting war dead that I had ever seen.
Melbourne 360 Deck
Victorian Market
Tasmania
I went to the eastern shore which was quite interesting. It is excellent for people who enjoys beaches, camping and sightseeing. Pyengana Valley is the most beautiful spot in Australia that I had ever seen. It has very much reminded me of some beautiful valleys in Europe. Also if you want to experience their rain forests, you can drive thru Myrtle Forest which is beautiful and amazing. Beware of their roads!
Also I suggest you to go to several natural wildlife reserve parks there. The one that I went is East Coast Natureworld which is amazing. It is where I held a wombat and petted kangaroos, tasmanian devils, wallaballies and others. Even they let you walk into large cages and watch some birds fly around and over you.
Binalong Bay - it is a lovely place where many young people go to beach for surfing and also some rich people own some beautiful mansions there.
I spent only three days in Tasmania and I realized that there were much more that I wanted to see there.