One thing I discovered is that when I stood up for myself with some people they turned mean and nasty and some even went so far as to be vindictive. But, the majority of people I've approached as if I thought of myself as decent and that I was deserving of decent treatment actually treated me decently. Your boss may have been concerned about your well-being; you don't want to borrow trouble by assuming all people (or most) will be mean to you. In fact, I now approach people with the attitude that they WILL be nice to me. Very few let me down. And anyone who is mean to you should be addressed firmly but calmly. If you want to quit your job, call your boss and say "I want to turn in my resignation, and I thought you should know that the reason I am quitting is that I find the uncertainty of the scheduling to be too much of a problem for me." You could go on to cite the snafu with the triple shift as an example of how that kind of scheduling just won't work for you.