Why is the international dateline drawn in a zigzag manner?

The International Date Line (IDL) passes through the Pacific Ocean. It is an imaginary line, like longitudes and latitudes. The time difference on either side of this line is 24 hours. So, the date changes as soon as one crosses this line. To avoid any confusion of date, this line is drawn through where the sea lies and not land. Hence, the IDL is drawn in a zig-zag manner.