1.  I was annoyed about the transportation system.  I did not like the thought of having to take a bus, walk or take a train to everyplace I wanted to go.  I felt very inconvenienced and missed my car.
2.  I was really nervous and scared about taking the trains and buses.  I didn't know how to speak Italian to even purchase tickets.  I also worried about how to get to the places I wanted to go once I got off the train or bus.
3.  I still get a little worried about what is going to happen once I get off a train or bus to a different place.  For example, tomorrow I am going to take a bus to Rome.  Rome is such a big city.  I don't know where the bus is going to drop me off and I don't know how far I will be from my hotel.  Other than that, I don't mind taking the buses or trains.  I actually like them because they are a lot less stressful than driving.
4.  I was just forced to use the trains and buses so I began to feel more comfortable when using them.  It was just practice.
5.  With trains and buses, I appreciate that public transportation is available to almost anywhere.  In the United States you either have to fly or drive.  As far as walking, I really enjoy the "walked in" city feel of Siena.  I like being able to walk anywhere and not be exhausted by the distance.  I feel like it is a better community.  I wish Seattle were like that.
6.  I will miss walking everywhere I want to go. Back in the United States I feel less of a sense of community.  
The thing I will miss the most is public spaces like the campo.  A place for everyone to meet and relax.  The only place I can think of in the United States is Central Park.  We need something like that in the United States for people to meet.