I had a pizza in Sweden once with banana, seafood and curry powder and honestly it was better than most of the authentic Italian pizzas I have tasted.
My complaint with pizza with ham and pineapple is that it doesn't combo that well. I have no problem with the pineapple, but the combination doesn't enhance the pizza flavor, there are better combos out there.
Also notice that a good quality margherita pizza had an incredible taste thanks to the tomato sauce.
Most tomato sauce I tried in north america are terrible.
I'm Italian, living in Canada.
I am not Italian, but I enjoy pizza. You might be interested to know that (ham and pineapple) Hawaiian pizza was the invention of a Greek-born Canadian.