And all their stories are of the "shady" sort.

It is better to know no stories than to know that kind.

It is better not to be called a good fellow than to win a reputation by always having a new story of the low sort ready on your tongue.
There are other and better ways of winning a reputation as a good fellow.

There are stories which are genuinely humorous and funny which are also clean.

No matter how much of a laugh he may raise, any self-respecting person feels that he has lowered himself by telling a vulgar story.