Here's the thing about the iPad:
If I'm sitting at my desk using my computer and my wife comes along and starts talking to me, I need to stop what I'm doing and pay attention. But I'm still sitting at my desk. I start to get uncomfortable, like "I'm sitting here but must resist looking at the screen".
If I'm sitting on the couch or laying in bed using the iPad, and the same thing happens I can toss it aside. I can throw it around in a way one can't with a laptop. And then I'm sitting there, comfortable, and can listen to my wife without getting fidgety.
It's a far more interruptable experience because when I return to it it's instantly ready for me to pick up where I left off, with no concerns for the battery life. (I don't have to make the laptop choice of: am I coming back in 2 minutes or 2 hours? Should I put it to sleep?)
And this has nothing to do with the great user experience of Apple's software. Just the form factor, so I imagine it would hold true for any similar tablet from another company. It's the kind of thing that's hard to convey, and took me a week or two of using it to realize.