@F96T12 DD VHO, I think I understand what you mean with driving (or biking) and seeing the HPS lamps and blue/purple sky.
But I definitely understand and agree with the constant re-appearing shadow. With me though, it's especially satisfying (and cool)
when seeing the shadow from the lights constantly appear when driving and definitely when biking. Like in HPS lit tunnels, or
anything like that.
I also understand and agree with seeing the dimmer image of a very bright arc tube... especially with cool ways of doing it,
like with what you described with the magnifying glass. I think I've done stuff like that before as well.

Another satisfying thing to me:
-HPS lit sky... the sky being illuminated by the HPS light reflecting off the ground during the night, then ricocheting off the clouds.
 

The smell drifting through from the kitchen as the banananana bread bakes. 

Taking the washing in minutes before it starts to pour down with rain. 

When a catses comes up and says hello. 

When a catses comes up and says hello. 

And lets you pick them up for a stroke and a cuddle 

Having a catses turn on their purring engine for you. 

Getting the oil changed in my car.  I love the feeling of driving on the highway, and imagining the fresh synthetic oil cycling through the engine and being good to go for another 5000 miles!    I also like getting a clean bill of health from the mechanic, too.  Today's first trip to the garage with my new Subaru Legacy revealed perfect hoses, belts, air filter, and coolant.  Had the oil replaced, all the lights checked, and heard that the tires had plenty of life left too.

Slamming the doors of old army trucks.  We jokingly compared it to a wineglass shattering, in terms of the sound.

Getting a formula on a spreadsheet to do what you want it to do.

When you see a bright light source and it is the only source lit (lets say it's a 250W HPS) and is placed dead center in a room that is the size of a large factory. Nothing blocking it, and the walls are grey but the ceiling is painted white. Basically the room is empty and windowless and even on all sides except the ceiling
You turn on the source of light and wait for it to fully warm up, once it's fully warmed up, you get about one foot away from it facing away from the arc tube. Then you walk closer to one wall watching your shadow become more sharp and crisp, as well as stretched.
When you reached the wall you can still see your shadow is very sharp and relative to your height. You turn around facing the light and lets say you're wearing a white shirt and you can still see that your shirt is illuminated with the orange light

Long story short, It is very satisfying to see how far the light goes until your shirt isn't the color of the light or until your shadow becomes hard to see. This just doesn't go just to HPS, it really goes to any source of light including the sun

Learning how to play a simple tune on the mandolin.

Learning how to play a simple tune on the mandolin.

Watching you enjoying yourself doing it 

Knowing that the one you love is never more than an arm's length away.  

Taking things apart with the help of 'Mr Smashy' 

Taking things apart with the help of 'Mr Smashy' 

The snag with this of course, is easy reassembly becomes somewhat difficult