I was in my university's co-op program, but didn't apply for any jobs. A couple of weeks after the interview period ended, a representative from the school's co-op program called me and said they had a company that was desperate for a co-op, didn't find any who were qualified during the interview process, and my résumé was the only one they could find that listed experience with C.

I took the job. Embedded systems, primarily extremely resource-limited microcontrollers. It was beyond anything they could teach a student on the job, so they really did need someone who already knew the language. That was apparently a difficult skill to find among students in 2003.

10 years and 5 positions later, all of my work has been in C, and I regret nothing. It's a practical career choice: the jobs are plentiful and the competition is not. Also, it's the best language :P