Nope!

Me: Joe, give that back
Joe: Nope
Me: Joe, are you poopy?
Joe: Nope
Me: Joe, lets go get dressed
Joe: Nope
Me: Joe, it's nap time
Joe: Nope
Me: Eat your food
Joe: Nope
Me: Joe, come here
Joe: Nope

Joe's favorite word: NOPE