TECHNICALLY, yes. Humans consist mostly of hard, difficult to chew muscle. It is for this reason that most human victims are often 'spit out' by sharks when the attack occurs. Great Whites are notable for this...they will often take a big bite, and realize that this is not their normal prey when their bite rips into muscle and not the fat that they are used to on seals and large fish. It is because of this that many victims are recovered, and not dragged into the depths of the ocean and torn to pieces. However, most victims die because of the initial bite wound, which often severs nerves and tears muscle and bone apart. Otherwise, this is wrong. Human blood is still blood...which drives sharks crazy. A bleeding human will draw sharks. It isn't that sharks don't like the taste, but rather they don't like the feeling of the human being in their mouth. However, not all sharks 'feel the same way'. Tiger sharks are known man-eaters...often referred to as the 'trash can of the sea', a tiger shark will eat anything, and humans are no exception. They are among the most common man-eater sharks that actually do EAT man. Bull Sharks are the same way...often a curious bite will turn into a frenzied attack. While a loan Bull shark will typically not drag an entire human to their fate, they will usually take off a limb or a huge chunk, and retreat with their new meal. Great Whites will sometimes take an entire human with them, but most Great White attacks result in a severed limb or massive bite wounds all over the body. Don't let this fool you...sharks WILL go after you if you are in their territory. Just because they don't particularly care for eating humans, that doesn't mean they won't make a meal out of one if they are so inclined. If you remember the story of the U.S.S. Indianapolis, which was honored in the film 'Jaws', that is one of the single most tragic and concentrated accounts of masive shark frenzies on humans in recorded history, and it goes to show that when you are in their environment, you are their prey.

mostly yes unless the shark is gyardos which are notoriously famous for their joy of human "feces" enough said

This is possible. there are many cases where a person has been grabbed then released, seemingly when the shark realizes that the person is not 'natural' prey. sadly, the damage they do to the person often ends in the person's death.