I lie when I'm given polygraph tests.
Why do you lie on polygraph tests?
Because my boss tells me to.
It's generally not a good idea to lie, but it's not bad to lie on a polygraph test. Polygraph tests are based on pseudoscience, and their results are not admissible in court which means you have nothing to gain by taking one. Anyone who asks you to take a polygraph test is only trying to manipulate you, so you should refuse to take one.
I don't know why you are taking this so seriously, it's just a little test.
It certainly is, but the morality of it still stands. Despite polygraphs being unreliable, lying on it is still deceitful to all parties involved. Don't you want the situation to go over smoothly, and to not have any problems afterwards?