We called them "old man rules". The practices you follow because you know you were burned badly and don't want to have it happen again.
- I don't remember why you always put Set NoCount On at the top of the procedure but I always do it.
- I don't remember why I don't want any triggers in the database but I know that I don't.
- I don't remember why I don't want cursors in production procedures but I know that I don't.
Many of them are captured in Phil Factor's Code Smells.
But just because they are Old Rules does not mean they are bad rules. Nested Views are the devils spawn and lead to perdition. I wish I could set up a review council to test every trigger, view, cursor, etc. prior to going to production. Actually, it would be nice just to get a few coding standards in place :).