you can't quit a job without having a new one to go too ... thats how I look at it. sure your job may suck, but it pays the bills...
in the last year I've...
done courier delivery (great pay, lots of hours, just not feeling driving a cubevan around in the winter so I quit)
shipping\receiving at an electrical distributor (good job, good folks I worked with, pay was ASS so I quit)
and my current job: assistant manager at a construction\industrial supply chain (just got a raise, easy enough job, just not too down with working in sales..)
I'm going to use what I'm doing now to pay my car off, and then go back to school ... or try and weasel my way into a partsman apprenticeship