Actual wage theft, or contractual changes. For instance, no good pandemic is being wasted either in politics or in the hospital sphere. So your hospital employed Big Box shop says for The Our Greater Good we will cut your pay 20% until Flattening the Curve Covid is over, and here is your new contract.
Or you have a clause in your contract that says you get X bonus or this much pay for meeting certain wRVU numbers, but then they say, nope. We won't pay that.
Just in my career I have had a few instances contract terms being ignored and with it a price tag of several thousand dollars. So the question is, how much are you (or have you) been screwed over financially before you say you will walk away?
This could perhaps manifest in VA docs who should get that bonus but then they don't, or their student loan package but then they don't. This list is endless of how this could present.