One life lesson I learned that (I firmly believe) really helped me out in my career was being 'stuck' working at a car dealership. I worked as a lot attendant, parts advisor, service advisor and then sales advisor over the course of 7 years. Part time during the year, full time during the summer. Paid off my entire education with that job. Each aspect helped me gain skills that were important later on. But the most important one was talking to people from all walks of life. From the stupid rich, to the normal 'worked off my whole life and now I want a Jag' folk it was a very good learning experience.
Sink or swim, sales will ALWAYS be in demand. Maybe not directly...but you need to negotiate with your boss, co-workers, stakeholders, contractors, and everyone else in your life...there is always negotiations and car sales really helped me out.
That opened a door to a career in technical sales in the water and wastewater industry...then that helped me move into the heavy civil world I'm in now working on underground projects....meanwhile I graduated in Aerospace Engineering...go figure.