We all know when to use a comma, right? Well...not really.
Some writers sprinkle commas into their sentences like fast-food chefs sprinkle salt on French fries; the more commas/salt, the tastier the sentences/fries.
Other writers avoid commas like they're the plague, either out of fear of misusing them, or because they really don't see a comma as a necessary punctuation mark in certain sentences.
(Of course, the most common reason writers omit a needed comma is because our fingers are flying over the keyboard faster than our brains can spot our mistakes!)
The T-shirt example above shows how a sentence can be misunderstood when the comma is omitted. The most common comma error I see when editing manuscripts is the omission of a comma between an exclamatory word (hey, oh, wow, etc.) and the name of the person or term of endearment following that word.
Example: "Hey Tom, let's go!" should be "Hey, Tom, let's go!", or even better, "Hey, Tom! Let's go!"
In the same way, "Oh honey, you look so worried." should be "Oh, honey, you look so worried."
In the first example, Hey Tom is not the man's name. It's Tom, pure and simple, so insert a comma. As for the second example, terms of endearment--honey, dear, sweetheart--are always separated from other words by commas, regardless if they start, end, or are in the middle of the sentence.
Another common comma error occurs when words are listed in a sentence. Lists of three or more words should be separated by commas.
Example: "I went to the store with my uncle, cousin, brother and best friend."
Read this way, the speaker went to the store with three other people: an uncle, a cousin, and a brother who is also the speaker's best friend.
This could be true, but what if the speaker actually went to the store with four other people? Then the sentence would have to be written this way:
"I went to the store with my uncle, cousin, brother, and best friend."
Now we know the brother is not the speaker's best friend. The best friend is a fourth person accompanying the speaker to the store.
A well-placed comma is a writer's friend. On the other hand, too many commas can annoy the reader. Why? Because they usually occur in sentences that are too long, too descriptive, and/or too complicated to be easily understood.
Consider this sentence:
"I was going to the store when, much to my amazement, I saw a bird, smaller than a hawk, but larger than a dove, fly into my neighbor's tree, the one by the corner, not the one in the yard, where it began pecking at the trunk in a most unusual, but not unpleasant, way, until my neighbor's wife, her long, golden hair streaming behind her, ran out of her house brandishing a spindly, brown broom in one hand and a dirty, wet dishtowel in the other while screaming at the bird in a loud, almost raucous, tone of voice."
An annoying sentence? You can say that again! :)