Makes me think of the time I consider my first actual IFR.
I was heading to the east coast with wife and 2 year old daughter from Reno in Sep. 78 in our Mooney M20E. As the first day was getting long over the plains, I decided to stretch the flight to St. Louis. I'd arrive some hour+ after official dark, but we had plenty of fuel and the conditions were clear with 3mi vis in haze, not predicted to change. I had a sister living there and we'd arrive that evening instead of the next day for a short visit.
As dusk fell and the sky darkened, we could see a couple bright stars faintly, and the occasional farmhouse light occasionally, and the horizon not at all. Couldn't really tell the difference between the farmhouse lights and stars, and there were plenty of times when neither were visible. The last hour of flight was definitely on the gauges & VORs, and knowing that it wasn't a practice flight.
Everything was in order and went fine. When St. Louis lights finally came into view, I could relax and stop feeling I had to be at absolute max performance. We could again tell where the ground was.
I had been training for IFR, done my cross country with some actual with the CFI sitting next to me. I was current for night landings. I knew the skills were there in case they were needed. I didn't expect, though, to need them so thoroughly. It's one of those experiences I will never forget.
Don't let any of your low-time students loose in 3mi "VFR" weather at dusk!
Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity, or neglect.