There are several differences between Italy and most Anglo-Saxon countries such as the UK, USA, Australia.
There are many sources on this subject, your best bet is to read up ahead of time. We won’t get into the all detail, but will limit ourselves to a few observations made in the course of our stay in Italy.
First of all, not all Italy is the same – there are significant differences between the Italy of the different regions – from the more reserved Piemontese to the more vivacious Neapolitans, one of the key issues to keep in mind is that people will tend to reflect characteristics of their local area.
Another thing to note is that relative to other European countries, the level of English knowledge in Italy is very low. So unlike in more northern European countries, where it seems like so many people speak at least a bit of English, in Italy these people will tend to be fewer and further in between. It may be less evident in the expat community or in popular tourist areas, but you will still be confronted with it, say, when the bathroom is leaking and you are trying to call a plumber. So it cannot hurt to get the basics of Italian. Not only – this will be much more appreciated than in certain other countries northwest of Italy, where if you don’t speak their language perfectly you are considered a barbarian.
Lining up. What can I say, Italians don't! It has gotten better in recent years though so all hope is not lost. If you arrive someplace (the doctor's office is a good example) you need to ask who is the last in line (chi è l'ultimo?) and then you will know that you are after the person that responds.
Dropping in. Italians show up unannounced quite often. Don't be surprised by this. If your house is normally in a state of CHAOS (Can't Have Anyone Over
Syndrome) then at least make sure that your entryway is nice and tidy.
Do you have more examples for differences? If so drop me a line firstname.lastname@example.org and I will be happy to include them.