Let's say you like tomato sauce very much and you buy too much of it. Your neighbor three doors down from where you live is found dead one day in his bathtub. He was drowned in tomato sauce which the bathtub is full of.

You're the prime suspect, even though you didn't even know your neighbor, you've never spoken to him in your life and didn't even know he existed. The only incriminating evidence the police have found on anyone so far is your purchase history (or maybe you also googled for "death by tomato sauce drowning" once when you were in high-school?). If everything turns out alright you enjoy being interrogated for a few days and have a good story to tell for the rest of your life.