In a job that did not reflect who you are, how would you keep a sense of self?

I know and realise that most people dont enjoy their jobs, and probably face the same dilemma. But lets say the job you “had” to do, upset you, or disturbed you, but you had no other choice. How would you maintain balance in your life on a daily basis? It could be a job that goes against everything you believe, but you simply have run out of choices. I think really I am looking for the “balance” factor or the fact that people can have healthy lives, even if they have very difficult jobs. Or because they do not have choices in one area of their lives, does it filter through to other areas of their lives?