why was y2k scary 
experts feared that the switch from the two digit year 99 to 00 would wreak havoc on computer systems ranging from airline reservations to financial databases to government systems for instance the banking system relied on dated computers and technologies and it wasn t irrational for depositors to worry about being able to withdraw funds or engage in important transactions bankers were worried that interest might be calculated for a thousand years 1000 to 1999 instead of a single day 