You may think there's such a thing as "your" copy of Shrek 2, that you "own" -- but if you're talking about a DVD, then you don't really own it.
Why-what-how, you ask? Well, "owning" something means you're in total control of it, does it not? Like, take any book you own with you on a trip, and you can read it in Malaysia as well as Monaco; in Equador as well as Eritrea.
Try that with a DVD -- come here, for instance, and pop it in the player at my in-laws' -- and it'll refuse to play. It does that because that's the way mr Jack Valenti of the MPAA wants it, and he -- not you! -- is actually in control. So, no, you don't "own" Shrek 2; Jack Valenti does.
HTH!