I ponder "-ing" words

Writing and editing are a part of my on the edge of ordinary life. I wonder if some of the things I've learned could be of help to you?

When I started writing seriously and got into a critique group I learned some interesting things that my English teacher never taught me (or I can't remember that they did). One was that 
"-ing words are bad". That took time to digest! 

I now know that if you trim the "-ing" words (verbs in the progressive form) out of your writing you end up with writing that is more direct and has less flab. I find often when I'm in the middle of an edit that I'll suddenly realise that this writer has overdosed their writing with "-ing" and I take some time to trim it down.

It's a common writing problem. However I probably couldn't have given a concise reason for why excess "-ing" words are bad. This blogger, however, has here: 

When overused, -ing words in the progressive forms (whether past, present, or future tense) introduce too many weak, little words like am, are, is, was, were, been, have, has, and had—and more. These are helping verbs that the progressive forms require: I was running, I will be running, I am running, I am going to be running, and (though not often used) I will have been running.

In the end simple present, past, or future tenses give more concise writing. So now I try to choose my verbs more carefully. Instead of the first words that comes to mind, for example: "She was really shouting." I would rather choose "She yelled." or "She bellowed." 

Can you see how this is stronger writing? Can you find something you've written and eliminate some of the "-ing" words and see how it changes your writing?