For simple lists, items should be added to the bottom of the list by using a tertiary button with a plus icon. In this case, the adding should be inline and not open a modal dialog. Simple lists never use paging.
Simple lists can also be read-only. These are usually in widgets or read-only views.
Use a fat list when additional data/images are needed to clarify the given objects in a list.
Case widget lists are often tiny, but hide a lot of complexity in the data objects they display. Items should be added to case widgets via a modal dialog that is launched from the upper right of the widget header by using a tertiary button.