I believe that maintaining high standards is what keeps us above the animals. Indulging our basest desires cannot possibly be good for our subconscious. If rehearsing things in dreams has the same effect as rehearsing them in real life (which it does), then surely whatever else we do in dreams will have a similar effect on us. If you have a deep-seated urge to murder or rape someone, do you really think it's good for you to indulge it, even though it's not real? I sure don't.

So that means no violence against humans (except in self defence), and no hows-your-father. To be honest I would love to have a bare-fisted fight to the death with a DC, but yeah, probably not something I'll attempt to indulge.

Other stuff like stealing is OK, as long as the DC doesn't get upset about it - I'd feel too sorry for them if they did.