Or you could alternativelly try something like the following:

my @acceptable = ('good', 'bad', 'iffy');
while(<>) {
    chomp;
    my $input = $_;
    foreach (@acceptable) {
        next unless  $_ eq $input;
        print "You are feeling $_!";
        undef $input;
        last;
    }
    unless( $input) {
        print "You didn't give an acceptable answer! Try again:\n";
    }
}
[download]

Update: fixed a small error.