Newton's first law of motion states that The velocity of a body* remains constant unless the body is acted upon by an external force.
This would explain why, even though I'm feeling like shit, I'm still sitting at the kitchen table looking at shoes on ebay, instead of going to bed. Inertia. Do you think I can get some kind of tablet for it?
As for the external force... Well, it's a race between my laptop battery running out and Dad coming and telling me to go to bed.
Do you think he'd get it if I said to him "But Daaaad, I've got inertia..."
He'd probably say "well go to bed then." He might really like watching The Big Bang Theory but I don't think he gets any of the physics jokes.
*In this case, my body.