'Do as I say not as I do'. Who hasn’t heard that? (“Haz lo que yo digo no lo que yo hago”). Is that really a good example? It’s true that when saying the whole phrase you’re explaining what the person in question has to do and what example follow… but is it really a good example? If it’s wrong, why don’t you stop doing it too? You won’t harm anyone and you’ll be a good example to be followed.
There’s another phrase that I like much more than that one, and says:
'Do as you say, not as you do'. That is what should be done! Why telling me not to do something you also do? If you don’t do it, then maybe I understand that it is really wrong.