Do certain issues or governments tend to reproduce consistently either policy underreactions or policy overreactions? This chapter elaborates on the psychological and institutional explanations that can account for unintentional policy over- and underreaction styles and the strategic explanations that can account for their intentional counterparts. The arguments advanced in relation to psychological and institutional explanations are that policy over- and underreaction styles may occur as a result of psychological biases and strong emotions, as well as due to institutional values, procedures, myths, and routines. The arguments advanced in relation to strategic explanations are that (i) real or manufactured policy problems, especially in the areas of national security and crime prevention, may produce overreaction policy style because political executives wish to display their unwavering commitment to the resolution of problems by implementing aggressive and visible policies as well as by overspending on the military and police, and (ii) real or manufactured policy problems to which government supporters accord low priority may produce underreaction policy style, involving symbolic action and neglect. These disproportionate policy styles are likely to be pronounced when populist leaders hold executive positions.