Note: sharks don't like eating people as our bones are too dense and we lack fat. However they are both peckish and curious and their momma's teached them not to pass a meal without trying it first.
Plus some sharks (e.g. great whites) use their teeth for tactile feedback.
Unfortunately, when bitten, we tend to bleed out quickly in the water and that's what often hurts us badly.
Crossing the street guy looks like he was smuggling Garfield and Stimpy in his shirt when he died.