A little while ago, I joined the élite ranks of those few who have literally debugged a system. It seems that the garage door here wouldn’t close properly. From the symptoms, I knew it was a problem with the infrared detector system believing something was in the doorway. After some testing, I was able to confirm my diagnosis.
After efforts to realign the sending unit and the sensor failed, I started to disassemble the system. I intended to try to aim the sending unit at the receiver manually to confirm functionality, since you can’t see infrared. In the process, I noticed something inside the little box holding the infrared sender. I couldn’t tell what it was though, so I started to disassemble the box to find what was in there. As soon as I opened the box, a dead moth of some sort fell out. I told my roommate to hit the button. The door closed perfectly.
So yes, I have now quite literally debugged a system. I think that Admiral Grace Hopper would be proud.