I believe that the first week of the course is the most important week of the session/quarter. It definitely sets the tone of the course. (I remember back when I was a college student and would form opinions of a course during the first class meeting). It is sometimes hard to change those opinions once they are formed! So I really do think the first class meeting is extremely important and it is essential for the instructor to be prepared and start the course on time. I also think that expectations of the course need to be discussed during this class meeting. I always use the first half of my first chat/class to go over what my expectations are regarding participation, attendance, assignments, etc. If I, as the instructor, provide good, clear expectations, the students are aware of what is expected, which I believe helps the students to be successful in the course.