Some sections of the Home page are displayed only if there is a content to display.
If you want to have them always shown (even if empty), set the following keys in Advanced Configuration Options to true:
alwaysShowMyPendingApprovalsalwaysShowMyPendingCreationWorkflowsalwaysShowMyToDos
The settings made here using the Advanced Configuration Options have lower priority than settings made in Configuration > Home Page (where you control visibility of the Home page panels).