A very expensive box- Exactly what do you get when buying computer software "off-the-shelf"?

Imagine that you go to one of the major electronics stores, or perhaps a department store. You find a computer game that you like, take it to the checkout, pay for it and bring it home. When you get home, you eagerly rip open the package and insert the CD-ROM in the CD drive of your computer. Having spent 5-10 minutes waiting for the game to get installed onto your hard drive, you are asked to click "I agree" to a lengthy License Agreement. Do you read the agreement? Perhaps you should.