Justification 1: I was on a secret mission, and I couldn't possibly reveal it to you.
Justification 2: Reorganizing the world
Justification 3: Finding the perfect meme
Justification 4: The coffee shop down the street was having a sale, and I just had to get some coffee.
Justification 5: The apocalypse is coming, and I had to prepare for it. Can't be bothered with mundane tasks like this one.