It's less about what I expected, but more about what I did not expect.
The pace of technology change has accelerated dramatically, the complexity of software has grown beyond imagination, and perhaps correspondingly, the fragility and interdepencency has grown out of control.
We (myself included) have become so acclimated to complex software as users that we forget how much work is buried under the surface of a "simple" app. Even accurately describing the behaviors of a system is difficult now (and often not even documented, partly because it changes so often).
When I was taking flying lessons in the 90s, I couldn't believe how antiquated and manual-intensive the aircraft systems were. There seemed to be so many places where pilots needed to follow a checklist to perform manual tasks which could have been automated based on various available data. When I asked my instructor why it was so archaic, he explained that it's a long and arduous process to get new things certified by the FAA.
This difficulty in getting advanced systems approved was mostly due to the processes and tests required to ensure a very high standard of reliability and safety, since lives were at stake. At the time, I thought it was ridiculous. But seeing some of the Airbus automation problems (which cost a few aircraft and some lives), and then seeing the Boeing 737 Max disasters, I see how slower advancement, more testing, and slower release cycles can be beneficial.
But in the software world, the more modern approach is "move fast and break things". Not only is software now never complete (in contrast to when software was released once or once per n-years, on disk or CD), now it is released every 5 minutes with old bugs replaced with new bugs. There are days where every time you open an app, it needs to update first. I'm not sure this is a net improvement.
If I could say one really positive thing, it would be that tooling has gotten really nice. Even I recall when syntax highlighting arrived... and at first was laughed at. On the other hand, the better tooling is virtually required to keep up with the ballooning complexity and volume of the code we write.
I could rant and complain many more paragraphs, but it can be summarized thusly: modern software (and its development) has made some great improvements, but those improvements have been largely offset by reductions in the quality and formality of practices.