The things Apple sued Samsung for were not trivial. They were essential contributors to Apple's trade dress. Samsung "borrowed" those items to confuse the consumer into equating Samsung products with the iPhone. The fact that these were additionally patent violations compounded the offense.
In summery:
- Samsung copied from Apple, and Apple copied from Samsung.
That's what it boils down to.
This is essentially the Windows vs Mac OS X argument from 2007.
It'll end the same way: A settlement where both parties carry on as normal with very little change (if any) to the product, and a hell of a lot of money lining lawyers pockets.