Flagged items and Context items: can't get them to work

I have created projects and actions, and I have flagged some of my actions, and some other actions have been assigned to the “waiting” context. Despite that, whenever I click on the “Flagged” perspective or on the “Context/Waiting” perspective no action shows up. The lists are empty.
What am I doing wrong?

It seems you have the wrong filter on your view. Clicking on the View icon (or type ⇧⌘V) and playing with the options in there might be the solution.