1) Implemented a new automated web testing framework. Next year, I'll do the same thing for Android and Apple phones.
2) Migrated some of my control system apps to C#. Three months ago, I didn't know C#.
3) Migrated more system control software than I care to think about from VBScript (awful) to Powershell (slightly less awful).
Four years ago, I didn't know what virtualization was. Today, I'm in charge of the VMWare servers and couldn't do without it.
I have no idea why I can still do this. Like the other commenters here, however, I do regularly cringe at the latest business/software/process fad. They're inevitably retreads of something older and few add any actual improvement. Powershell, for example, although it packs more functionality into fewer characters than VBScript, made the skill set of thousands of system administrators obsolete. No thought was given to the human side of the system. A more useful solution would have been a rewrite of VBScript and the addition of useful function libraries and easier access to the net framework. It was yet another typically wrong Microsoft decision, but it says something about an industry that doesn't have enough of a balanced view to consider the cold, hard neurological facts of their user base.