I first saw Linux in action around 2001 at my first job. I was as an account manager for an Austrian automotive industry supplier and shared an office with our IT guy. He was creating a CD burning station (one of those huge things that can burn and print several CDs simultaneously) so that we could create and send CDs of our car parts catalogue to customers. While the burning station was originally designed for Windows, he just could not get it to work. He eventually gave up on Windows and turned to Linux, and it worked flawlessly.
For me, it was all kind of arcane. Most of the work was done on the command line, which looked like DOS but was much more powerful (even back then, I recognized this). I had been a Mac user since 1993, and a CLI (command line interface) seemed a bit old fashioned to me at the time.
It was not until years later—I believe around 2009—that I really discovered Linux for myself. By then, I had moved to the Netherlands and found a job working for a retail supplier. It was a small company (about 20 people) where, aside from my normal job as a key account manager, I had involuntarily become the first line of IT support. Whenever something didn't work, people first came to me before calling the expensive external IT consultant.
One of my colleagues had fallen for a phishing attack and clicked on an .exe file in an email that appeared to be from DHL. (Yes, it does happen.) His computer got completely taken over and he could not do anything. Even a complete reformat wouldn't help, as the virus kept rearing it's ugly head. I only later learned that it probably had written itself to the MBR (Master Boot Record). By this time, the contract with the external IT consultant had been terminated due to cost savings.
I turned to Ubuntu to get my colleague to work again. And work it did—like a charm. The computer was humming along again, and I got all the important applications to work like they should. In some ways it wasn't the most elegant solution, I'll admit, yet he (and I) liked the speed and stability of the system.
However, my colleague was so entrenched in the Windows world that he just couldn't get used to the fact that some things were done differently. He just kept complaining. (Sound familiar?)
While my colleague couldn't bear that things were done differently, I noticed that this was much less of an issue for me as a Mac user. There were more similarities. I was intrigued. So, I installed a dual boot with Ubuntu on my work laptop and found that I got much more work done in less time and it was much easier to get the machine to do what I wanted. Ever since then I've been regularly using several Linux distros, with Ubuntu and Elementary being my personal favorites.
At the moment, I am unemployed and hence have a lot of time to educate myself. Because I've always had an interest in IT, I am working to get into Linux systems administration. But is awfully hard to get a chance to show your knowledge nowadays because 95% of what I have learned over the years can't be shown on a paper with a stamp on it. Interviews are the place for me to have a conversation about what I know. So, I signed up for Linux certifications that I hope give me the boost I need.
I have also been contributing to open source for some time. I started by doing translations (English to German) for the xTuple ERP and have since moved on to doing Mozilla "customer service" on Twitter, filing bug reports, etc. I evangelize for free and open software (with varying degrees of success) and financially support several FOSS advocate organizations (DuckDuckGo, bof.nl, EFF, GIMP, LibreCAD, Wikipedia, and many others) whenever I can. I am also currently working to set up a regional privacy cafe.
Aside from that, I have started working on my first book. It's supposed to be a lighthearted field manual for normal people about computer privacy and security, which I hope to self-publish by the end of the year. (The book will be licensed under Creative Commons.) As for content, you can expect that I will explain in detail why privacy is important and what is wrong with the whole "I have nothing to hide" mentality. But the biggest part will be instructions how to get rid of pesky ad-trackers, encrypting your hard disk and mail, chat OTR, how to use TOR, etc. While it's a manual first, I aim for a tone that is casual and easy to understand spiced up with stories of personal experiences.
I still love my Macs and will use them whenever I can afford it (mainly because of the great construction), but Linux is always there in a VM and is used for most of my daily work. Nothing fancy here, though: word processing (LibreOffice and Scribus), working on my website and blog (Wordpress and Jekyll), editing some pictures (Shotwell and Gimp), listening to music (Rhythmbox), and pretty much every other task that comes along.
Whichever way my job hunt turns out, I know that Linux will always be my go-to system.