I looked at your pictures and immediately had to listen to Bach's
Toccata and Fugue in D Minor! Three times in a row, in fact, before I was satisfied.
Two recent projects spring to mind - I became fixated on both and spent way longer than I needed to on the details.
The water wheel - I know there are at least three CC water wheels out there which would be far better if I decide to build a mill, but the idea suddenly popped into my head of assembling a water wheel out of some bits of furniture, using angled OMSPs, and I had to try it right away. Eight tables, sixteen AL shelves, and far too many OMSPs - then I noticed that the lot I'd built it on had a cluttered background and I had to plant a bunch of trees in the road so I could take a clear picture of what I'd done. Then I thought it over and realised it would be much, much harder to position everything over a pond, where it would need to be - and it wouldn't be visible in hood view anyway. So that was a fun waste of time!
The goods wharves - there's the stone warehouse with the harbourmaster's office over it and piers for unloading barrels and crates from Hexameter's
restored pirate ship. Plenty of decorating, putting nautical paintings in the office and barrels and straw and ginormous jugs (amphoras of oil or something) in the warehouse. But I thought the beach needed quite a lot of rocks and seaweed, and then I became discontented with the two bits of driftwood in the game and added some other logs, and then I hit on the idea of tipping over a dead tree on a 90° OMSP - of course, since the tree is meant to stand on the ground, it doesn't have any polygons underneath, so I had to hide the disconcerting hole with more logs and rocks. And the seaweed hanging in the tree branches is meant to go on the ground too, so it doesn't have visible faces on the underside - I rotated the camera and thought it had gone missing at first, then solved it by hanging another seaweed facing the other way.