There are ethical problems quite close to home.
For instance you work for an organization that doesn't properly take stewardship of the resources it has and it turns into disaster.
You work for Company A which has customers B and C. B is a more important customer of A, so you work on B's project instead of A's project. Now "C" asks you why his project is late: the triangular conflict is a much better situation than 'we are floundering' but if you tell C about it you will get you in trouble with both A and C.
In that case, C might ask you to quit working for A and go work for them but you have a contract that says you're not going to walk off with a customer.
Problems like that can sneak up on you long after you're involved with a "gig" and feel like you have enough chips in the pot that you get "frog boiled" into making a mistake. See
https://en.wikipedia.org/wiki/Moral_injury