What motivates you to keep going in a biotech job?

I'm not a scientist myself, but I've visited several different labs and manufacturing sites of various shapes and sizes and talked to people in the biotech industry. The shifts are typically long, the work complex, and there is often a chronic lack of sunlight in the workplace.

Despite all that, people working in biotech jobs seem to be very motivated to keep going. Just curious what it is about your job that makes you want to turn it into a life-long career.