My first rotation as a 3rd year medical student (determined randomly at my school) was psychiatry.
Your first day on clinical rotations you never know what to expect. I was assigned to evaluate Mr. Binford, who'd been picked up by police (for vandalism) the night before.
I sat down and nervously spoke to Mr. Binford. He was a bit disheveled, but seemed intelligent and reasonable. He owned a home improvement company. He employed several handymen (including himself) and had a central dispatch office. They did all ranges of home and yard work.
It all sounded pretty reasonable to me. So, being young and naive, I presented the case to my attending psychiatrist. When he asked me what I thought, I told him that this person didn't seem to need psychiatric care.
Then he asked me if I'd read through his past chart. Sheepishly I admitted I hadn't, because I'd been in a hurry to interview the patient early on my first day.
So he handed me the chart.
OMG
The patient owned no such business. He had a remarkably intricate delusional system.
He owned a truck full of power tools, paint, and various other home repair supplies. Of which he had
some knowledge about using them.
He drove around the city, day and night, and would randomly stop at houses where he thought they'd called him for work.
People would come home (or be woken up at night) to find him doing unneeded work on their houses. Cutting down trees. Painting their outside walls. Knocking holes for windows in their homes. Taking apart pool filters. In one case he'd actually painted a guy's car with house paint.
I learned that old charts were useful.
I also learned that even the incredibly delusional could make a lot of sense when you didn't know their background.
We called him "Psycho Home Repairman".
And to this day, if one of our neighbors turns on a lawnmower or other loud equipment after dark, I go to the window... Just to make sure.