How believable unto you is someone who says "do what I say, not what I do"? Any cred at all? Why?

"Parents say the darnedest things, don't they!"

Actually I do listen when an older person who's done something their whole life tells me not to do it and that it's not worth it.
It's because they have experience and they remember what it was like to be my age and they look back and recognize where they went wrong.
Of course you have to be careful because some people are a little jealous and they want the younger generation to suffer like they did.
I worked with a guy when I was a teen who treated me like crap and his only excuse was that he was treated that way when he started out.
I try to make sure that the older person I listen to has a pure heart and that they want to help me.

You just described police departments across the country. They tell you to obey traffic laws but they themselves break them at their convenience.

My father often said, "Everyone should attend church", but he only did when he was trying to manipulate someone. My brother learned to copy that. I just did not attend church. One reason of many is seeing so many hypocrites there, e.g. my father, my brother, a cousin, an aunt and a grandmother. My mother's older sister Aunt Junko was nearly ejected from her church for having an indiscreet love affair with a married man who attended the same church. The pastor decided that this indiscreet couple donated far too much money to the church to be ejected. In the Old Testament, God gives humans rules that he often blatantly breaks, and he gives humans permission to often break them as well. Here are more reasons not to attend church. A coach who is a fat smoker may give us good advice about physical fitness, but we should not imitate his behavior.