Don't see it, so don't feel it, so don't do it

That's the reason for laziness.

There's only so much that our memory can hold for us. When I don't see the list of tasks that I need to complete, sometimes I don't even begin until a few days have passed. 

Alternatively, when the laptop screen is the only thing we see - in that the facebook or the twitter screen - that's what we get reminded of, that's what we feel and that's what we do.