in analogy to the thread about programs you said goodbye to, I am curious about the programs that were of *unexpected* use to you. So, it is not so much about the programs that you grew used to simply because the purpose they were designed for suddenly started to make sense to you, but the programs that did something well you did not expect them to do at all.
I'll start with one:
In my academic life, much of the literature accumulates in the form of pdfs, straight from the journal websites, from colleagues, co-authors and the nifty copy machine in our institute that can mail pdf copies from hardcopy prints, journal articles etc to my account that I can OCR later.
Some of the pdfs on my Mac are duplicates, or even triplicates and many of them have obscure names. In order to weed out the duplicates, I first tried the usual duplicate finder tools to no avail. One, perhaps because I pressed a wrong button, even deleted ALL copies and shredded them instead of putting them into the trash.

Anyway, I ended up using Graphic Converter for this purpose, a wonderful graphics program. It has a "find duplicates" functionality which works not only with images but with pdfs as well. Which in retrospective makes sense because pdfs are images of sort. What really sets it apart from duplicate finders is the fact that it does not only rely on the text content and so finds duplicates of papers even prior to OCRing and displays them side by side. It even has a fuzzy search that would in principle allow to find similar pictures perhaps from different copies of the same paper although I haven't tested that.
What are your highlights? I'd love to hear about them.
Prion