My rule of thumb is to hesitate before giving advice if I can't come up with an anecdotal story to support it. Stories are more useful than generalizations because they come with the context, and can be dismissed in different contexts. At risk of presently breaking this rule of thumb, I'll give an example. When I notice code being structured with class inheritance, I'll point out a part of the codebase where I did similar, and how poorly it turned out, which someone can observe for themself. It started out nice, as it usually does, but devolved over time as complexity accumulated in parent classes to handle scenarios in child classes.