$hurr_durr = 0;
if ( $hurr_durr == false ) echo "This Works!";
if ( $hurr_durr === false ) echo "You will not see this.";
if ( $hurr_durr == "0" ) echo 'This also works!';
if ( $hurr_durr === "0") echo "You will not see this either.";
=== checks for exact variables and types. 0 is an integer which also used as false, false is a boolean, "0" is a string.