When working with anchor points and paths, you may sometimes need to see direction lines (handles), while at other times they may get in the way. You can show or hide direction lines for multiple selected anchor points. For a single anchor point, the lines always appear.
You can choose to show or hide direction lines on a per-selection basis, or you can set a preference for direction line display.
For a video on setting direction lines and points, see www.adobe.com/go/vid0037.