They really expect some hustle... some stores have baggers to bag the groceries for the customers, while my store does not. If you're a cashier, you're going to work your rear off. (I once worked for UPS and it was easier than this.) One or two more cashiers on the floor certainly couldn't hurt; it seems they try to do with as few as possible somedays, thus leading to lines and anxious customers. I go home hurting almost everyday. I have a friend that works in grocery at another location across town. He feel he works hard, too, while others just stand around; it doesn't always seem fair.
I was also a little put off when I returned to college (I'm in my early forties,) and gave them my new schedule. I was a coordinator for a year before that, and since I started school, I very rarely coordinate and my hours got cut WAY back. I wish I felt more supported as a student. I feel I'm much more professional than the person that took my position, and my coworkers and customers that have known me for a while agree. I do take it personally, because I was proud of the work I did and it was very important to me. If it wasn't for the benefits and the fact that I need them, I doubt I would stay.