I don't think I will ever get this style of music (trance)... Will someone try to clue me in
I'll give you my take/history for what it's worth. Back in high school in the early 1980s (yes, I had to fight off dinosaurs while walking there across the local ice bridge <g>), a friend introduced me to Kraftwerk through their album, Computer World (audio samples here). Since I was taking German at the time and loved computers, I was entranced (forgive the pun). I bought that and the rest of their albums and kept a lookout for similar music. As time went by, I learned that this genre has since been designated "trance" (Kraftwerk was sort of "ur-trance" before the term existed).
What I liked about it was the simplicity and complexity at the same time, as well as the electronic instruments used and the technological themes. Upon first listen it sounds very repetitive, and it is to an extent, but if you listen closer you'll find that it's also subtly evolving over time with new elements being added and existing ones changing. To me, this makes trance something like a simpler version of Bach's fugues with their complex and evolving structures.
I also soon found trance ideal to listen to while programming. Unlike Bach fugues (which are fascinating to listen to but require a fair amount of attention to appreciate), trance's structure doesn't distract me. Its simpler evolving phrases can be enjoyed in the background. And good trance provides a certain energy and something like a "dramatic soundtrack" while programming. One fine example of this is "Himalaya" which turns a coding session into something almost heroic <g>: http://imphenzia.homeip.net/imphenzia_tracks/Imphenzia.Himalaya.[Radio.Edit].ogg
I desperately want to understand what makes good trance and what makes bad trance and what it actually boils down to.
There's a fair amount of what I consider bad trance out there. Examples include extremely repetitive stuff that doesn't evolve over time and builds that go nowhere (accelerating drumbeats that seem to be building to a climax but which actually don't lead to new energy plateaus and instead collapse back to the same level). Also, while I enjoy some vocals (especially if by a female singer), some trance has too much for my taste - I prefer only a few phrases so that they don't distract the language-parsing part of my mind which is often busy programming while listening.