Everybody, even me, sometimes had to compromise on something, doing things we know to be wrong, and this happens doing whatever job in the world. But a singer must have the courage of saying no.
There are always good parts. They may not pay what you want, and they may not have as many days' work as you want, they may not have the billing that you want, they may not have a lot of things, but - the content of the role itself - I find there are many roles.
It doesn't matter if you try and try and try again, and fail. It does matter if you try and fail, and fail to try again.