When two independent clauses are joined only by a single comma, this results in an error known as a "comma splice."  In the example above, something more than a comma is needed to separate the two clauses. Replacing the comma with a semicolon is probably the most concise way to fix this sentence, while keeping it one sentence. The portion of the sentence that needs to be corrected is, "unique interests,"

In the example sentence both "I've had an incredibly long day" and "I worked for almost eleven hours" are acting as grammatically complete, independent clauses. Thus, the comma after "day" must either be replaced with a semicolon, or have a coordinating conjunction added after it. The other option would be to replace the comma with a period and make this compound sentence into two separate sentences.

In the example above, something more than a comma is needed to separate the two clauses, as both clauses are independent, meaning they could act as their own grammatically complete sentence. Should you choose to connect two such clauses into a compound sentence your choices are to replace the comma with a semicolon (and no conjunction) or to add a coordinating conjunction after the comma. The portion of the sentence that needs to be corrected is, "the other day, he'd"

The example sentence makes a comma splice error by attempting to connect two independent clauses into a single compound sentence using only a comma. The comma after lately either needs an appropriate coordinating conjunction added after it, or needs to be replaced with a semicolon (and no accompanying conjunction).

When two independent clauses are joined only by a single comma, this results in an error known as the "comma splice." In the example above, something more than a comma is needed to separate the two clauses. The portion of the sentence that needs to be corrected is, "office, I had" 

The two, equally grammatically correct, options to fix this sentence would be to add an appropriate coordinating conjunction or to simply replace the comma with a semicolon.

This sentence includes a comma splice. The comma between "now" and "I" either needs to be replaced with a semicolon or have an appropriate coordinating conjunction added after it. 

Note also that "I'm" is a correct contraction of "I am."

Here, the comma between "met" and "I'm" creates a comma splice, since it joins two independent clauses without an appropriate coordinating conjunction. The best option, stylistically and grammatically, to fix this sentence would be to add the coordinating conjunction "and" after the comma.

When two independent clauses are joined only by a single comma, this results in an error known as the "comma splice." In the example above, something more than a comma is needed to separate the two clauses. The portion of the sentence that needs to be corrected is, "snitch, if"

A comma should never end a list: "Carlos, Jim, and their sister decided . . ."

Without a comma to make the "fresh bread" an item on the list, the item is unclear: is "fresh bread cereal" an item, or "fresh bread?" We need a comma to clarify.