It was only fairly recently that my husband caught on to the difference between "fun punishment" and "serious bizness punishment." Needless to say, my life got harder at that point.

The worst in terms of making me feel really, really bad about what I'd done wrong was being told that I couldn't call him Master until he told me I could. Reminding me that serving him is still a privilege.

Obviously it can't be taken too far, but sleep deprivation is also a pretty good incentive to think about what one has done wrong -- not like "no sleep tonight," but like "you have to finish your task before you go to sleep" when the sub is already feeling tired.