I sipped my latte and explained that passive voice does not mean that your sentence is long and dangly, lacks action, uses abstract language, or is generally boring. Like a lot of grammar terms, "passive voice" isn't a very good name for what it happening here. It is easily misunderstood.

Passive voice is a phrase that we use to describe a certain kind of sentence structure. It does not refer to the meaning of the words, the kind of words you use, or the length of the sentence. It's the order of the words that matter. Here are some examples of sentences that are written in the passive voice:

Fred was punched by Bill.
The hilarious comment was made by James.
The ish was pubbed by Mike.
The book was read by Sierra.
A long, boring speech about traffic lights and turn signals was delivered at the national conference of the Australian Vocation Bureau in 1987 by Chairman Gloria Underpenny.

All of these sentences are grammatically correct; that is to say, there is absolutely no grammatical reason not to use them. As far as the grammar police are concerned, these are all perfectly legal. Or, to put it another way, no tickets will be issued by your English teacher.

So what's the problem? When we read American English, we are generally happier if the subject of the sentence comes first. We want to know WHO did WHAT.  And we generally want to know it in that order: first tell me who is responsible, then tell me what they did. If someone messes with the basic, common, ordinary, familiar order of  things, we tend to get a little nervous. Somehow, a sentence like "David compiled the index" feels clean, honest, and straightforward. But if you switch it up and say "The index was compiled by David," all of a sudden, it feels a little, well, sinister.

So the passive sentences listed above seem more trustworthy if we are more direct, if we use active voice, if we say them this way:

Bill punched Fred.
James made the hilarious comment.
Mike pubbed the ish.
Sierra read a book.
Chairman Gloria Underpenny delivered a long, boring speech about traffic lights and turn signals at the national conference of the Australian Vocation Bureau in 1987.

All of these have word order that basically has a person doing something with something or to something. We call that a subject-verb-object (S-V-O) sentence. So if I have a sentence like "The teacher cried" or "Jane is the new president," then the whole active/passive issue doesn't even apply. It only applies when you have this particular kind of three part sentence.

Here's the bottom line: In active voice, the person who does the deed is standing proud as the subject of the sentence. In passive voice, the person who does the deed is hiding like a shivering coward in the prepositional phrase at the very, very end.

But if passive voice isn't wrong, does that mean that there are times when it would be a good idea to use it? Yes, there are.

For example, when you are trying on purpose to hide the perpetrator:

The window was broken.
The motion was made and seconded. 
The building was finished.
The body was discovered.
The evidence was compiled.
The suspect was interrogated.

In things like committee meetings, official reports, scientific papers, philosophical explorations, scholarly treatises, and so on, passive voice is not only permitted, but can be downright useful.  Passive voice can also lend a sense of authority to a piece because it evokes this kind of official, hifalutin rhetoric.

There are a few other situations, too. Sometimes you just don't know who was responsible. Or you want to downplay that information, or maybe you just want to save it for later. Or sometimes you need the stylistic variation to improve the flow of  your story. But in general, passive voice slows things down and makes people think you've got something to hide. It can be a little hard to follow. And it tends to sound just a little off.

Here, look. Here's the first paragraph of this blog in active voice:

A colleague called me the other day.  He offered to buy me a latte if I could help him figure out what was so bad about passive voice. I met him at the coffee shop on campus.

Here it is again, using passive voice:

I was called by a colleague the other day. An offer was made by him to buy me a latte if I could explain to him what was so bad about passive voice. He was met by me at the coffee shop on campus.

See what I mean?