On Sun, 23 Aug 1998, The Critic wrote:

I've decided to post small 'tricks of the writing trade' every once in a 
while to help unexperienced writers polish their craft.

I'm expected to take advice from someone whose English is so poor he uses
'unexperienced' where he should use 'inexperienced'?

Many unexperienced writers feel the need to explain facets of a 
character we already know (canonical characters, not new characters whom 
we naturally know nothing about). This practice clutters the prose, it 
can make the reader annoyed when the material contradicts his own 
perceptions of the character, and it's often taken by experienced 
readers, such as myself, as a set-up for an OOC description.

Or maybe you just don't know what you're talking about.

If the reader becomes annoyed that the material contradicts his own
perceptions, could it be... just possibly...  that the author's vision
isn't what the reader thinks it is?  Because...  just possibly mind you...
the reader needs a facet of the character explained to her?

In a nutshell--don't do it. You know how a character looks, acts and 
what is capable of, and so does the reader. It's acceptable only when 
done through the eyes of a new character who doesn't know anything about 
the canonical characters, and only then when it isn't gratuitous.

In a nutshell, quit giving out advice.