One thing I have encountered in teaching is the overwhelming inclination for students to lie, often without any reason.
I'll try to recreate one such event for you.
Imagine students sitting in their desks, preparing to journal. One girl near the front calls me to her desk. Her face is turned up anxiously: "Do you have any bandaids?"
Ever the accommodating teacher, I kindly reply, "Yes, they're next to my desk. Go ahead and help yourself."
Her face scrunches up. "Um...do you happen to have cream? Because, you know, the nurse always puts cream on first, then the bandaid."
I can't dispense creams as well as bandaids! There's no time for cream in English class! "No, I don't happen to have cream," I try to say in a straight face. I must have left my pharmaceutical stash in my other classroom.
"Well, I really need cream on my finger first. I'll need to go to the nurse."
Resigned, I quietly say, "Fill out a pass for me to sign."
Five minutes later...
The student enters my room and wastes no time before declaring, "The nurse was out of bandaids. Can I have one of yours?"
I acquiesed, even as signals went off. Who ever heard of a nurse's office running out of bandaids?! More specifically, a nurse's office in a middle school? Surely 98% of the students who want to go to the nurse only want a bandaid for a minor cut. Is there any possible world where they would run out? That seems to be something they would closely monitor. However, I wasn't about to judge our nurse if she had, indeed, lost sight of her depleting stash.
During my prep hour, I was near the nurse's office, and, to satiate my curiosity, I stopped in.
"Did you happen to run out of bandaids?" I asked. I tried to sound genuinely concerned, but I couldn't keep my amusement out of my voice. After all, it was a pretty fishy excuse and I was skeptical.
The nurse looked at me quizzically, walked to her cupboards, and revealed a multitude of bandaid boxes that were holding thousands of bandaids in all imaginable sizes. I told my tale, the nurse was aware of said student, and had seen neither hide nor hair of her.
It gets better. As I talked with the student the following day (after she asked for another bandaid), I informed her that I was aware of her deception and that she was not allowed to leave my room again. If you know me, you know I am not all that intimidating; I was firm yet kind. She held resolutely to her tale that she had been to the nurse and then proceeded to write me and threaten that "if you wanna be that way fine you will be gettin a note from my mom. Signed, You Know Who." I doubt anything will materialize out of this. If something does, I'm not concerned. After all, I happen to know the nurse's office has plenty of bandaids.
The thing that gets me is that had she just returned to my room quietly and gone to her seat, I probably wouldn't have even noticed that she didn't have a bandaid on her finger, and none of this would have been revealed. Guilty consciences can make you say the silliest things. And they can make you write notes that are better suited to a peer than a teacher.