The Naked This

I was rereading a bit of G4 today and came across a Naked This. I knew my high school English teacher would be ashamed of me. It was his ultimate pet peeve, and though I found it ridiculous at the time I have come to really appreciate this simple bit of advice.

Take these two versions of my sentence from G4

Naked This: This was evidenced by the fact that I had somehow managed to smudge a long dark line down my cheek like a morbid mime tear.

 

Clothed This: This ineptitude was evidenced by the fact that I had somehow managed to smudge a long dark line down my cheek like a morbid mime tear.

 

I find the second sentence so much more successful. The first begs the question "this what?" and even with a preceding context sentence, what "this" is can be a lot more ambiguous to the reader that the writer thinks it is. 

This advice is still my go to rule for clearing up ambiguity.