How to document use cases

Here's a great post about use cases. There I found this other great link about Five use case traps to avoid. Those are:

Trap #1: Use cases that users don't understand
Trap #2: Too many use cases
Trap #3: Overly complex use cases
Trap #4: Describing specific user interface elements and actions
Trap #5: Not using other requirement models

The first one is probably the one that trouble us the most.