In my case, the automation I've done has been in three main "hats" of software development: developer, builder, and tester. At one place I automated the installation process, which had a lot of quirks to it.

For instance: when a (Windows) installer starts up, there exists a "Next" button -- but it's grayed out for a few seconds while it's loading, and then become active.

So I couldn't just "wait for 'Next' button to appear", which I had written generic code for; I then had to write a "wait for 'control' to become active". And other similar hurdles.

Once completed, my automation would run at the fastest speed possible on the computer it was running on -- and no faster. It would never try to move forward when it was unable to. The sales/marketing folks really loved watching my demo!

There was one installer which was really poorly coded -- after user clicked the "Finish" button, and after the window goes away, it continued to do some processing. So I had to write several other routines for that: "what process is running this window?", so I'd know the process; and then after clicking "Finish", "wait for process to exit", and then I'd have captured all the actions that the installer took.

More recently I've been using Jenkins, a continuous automation server, to add post-build tests, and pre-checkin tests. Perl is my favorite scripting language, although Python is interesting as well. Not programming these days, I forget too much. Hopefully that'll change; we shall see.