On a recent Delta flight, I discovered I had been demoted.

Until this January, Delta boarding included a “Sky Priority” phase that put frequent flyers in the two middle tiers (“Platinum Medallion” and “Gold Medallion”) of Delta’s four-tier elite flyer program together with passengers sitting in extra-legroom “Comfort+” seats at the front of the coach cabin. But, since January, the Comfort+ passengers have been allowed to go before the mid-tier Medallion passengers like me, which means I often have to board later than I was used to.

Rough, right?

Of course, it wasn’t always this complicated. I am an old millennial, old enough to remember that airplanes used to be boarded from back to front. People needing special assistance and first class got to board first, but after that, you filed in based on your row number. That’s all changed, for two reasons, both of which can be thought of as technological advancements of sorts.

One thing that happened was that airlines discovered that boarding by row in reverse numerical order, while intuitive, is one of the slowest possible ways to board an airplane, because people bunch up trying to use the same bins and squeeze into the same rows at once. Even boarding in a random order is about 30 percent faster than boarding the old-fashioned way.