Mac OS 8 introduces the "View as Buttons" option for icons in open windows, allowing young or inexperienced Mac users to activate files or applications by clicking once instead of twice on the icons. The major drawback to this is that you can't move a button once it's in place, except with the "Clean Up" menu option, which doesn't always put the buttons where you want them. Other than that, the moment you click on a button, you launch it.

Here's a tip, though: click only on the name under the icon to select or drag it without activating it. You can even Shift-click on a number of buttons' names to move them all at once.