During my career as an In-Room-Dining Server, I've worked every shift - the morning shift, the afternoon/evening shift and even the overnight shift.
I didn't really care for the morning shift for two reasons: (1) I'm just not a morning person and (2) As busy as it usually gets during the morning shifts, there's not much money to be made. The cost of breakfast is much less than lunch or dinner.
The shift I absolutely HATE is the overnight shift. I find it to be the loneliest and the longest. Many times there's only one person scheduled to work on the overnight shift. As a result, you tend to do more work because there really isn't anybody to share the duties with.