A full 59 years before Jaws created a generation of terrorized beachgoers, people were worried about sharks and the possibility of being attacked. In fact, the fear should go the other way around, seeing as sharks kill about 10 humans a year but humans kill about 20 million sharks a year.
So to answer the title question: do sharks only attack when crazed. NOAA says they actually mostly attack humans when mistaking us for their typical prey like sea turtles or marine mammals.
Do Sharks Attack Humans Only When Crazed?: J. Ernest Williamson, Who Took Undersea Pictures of Them and Fought One, Declares Them Cowardly by Nature
From July 30, 1916