...the bill at various points has allegedly been favored for acts of election bribery, gambling, and prostitution. It's also been linked to the devil, necessitating the tearing of a $2's corners to ward off evil spirits.
While all these associations are now attributed to urban legends, there also may have been practical reasons for the corner-tearing tradition. As more $1 bills were printed in the 1880s, people who grouped smaller bills together would shortchange themselves when a stray $2 ended up in a pile of $1s. As a result, it became a common practice to rip a corner of a $2 to help avoid that mistake and ward off the bad juju of miscounting money.