Here, the phrase "a traditional dish from Japan" acts as an interrupting phrase in the sentence, disrupting the flow of the sentence for a contextual, not a grammatical, purpose. As such, the phrase should be separated from the rest of the sentence by commas.  As written in the example, there is a comma missing between the word "ramen," and "a traditional dish from Japan."

Here, "one of my favorite places in the city" is acting as an interrupting phrase, and should be separated from the rest of the sentence by commas. Note that if the interrupting clause is NOT correctly separated from the sentence with two commas, but rather only one comma is used, it will result in a comma error by separating the subject ("the science museum") from the verb "was closed."

"If you wanted to be absolutely certain that there were no mistakes" is an introductory phrase, and therefore it must be separated from the rest of the sentence with a comma. The corrected sentence would read: "If you wanted to be absolutely certain that there were no mistakes, you should have overseen the details of the project yourself."

The sentence above contains a dependent clause (a clause that cannot stand on its own as a complete grammatical sentence). Dependent clauses must be separated from the rest of the sentence, often using commas. This clause is also an introductory clause, and thus must be separated from the main clause with a comma after "dog." The best way to correct the sentence above is "While I was out walking my dog, it started to rain so hard I couldn't see."

The sentence above contains a dependent introductory clause. Such clauses must be separated from the rest of the sentence.  The best way to correct the sentence above is "After the rain stopped entirely, I finally managed to get all of my groceries in."

The sentence above contains a dependent introductory clause. Such clauses must be separated from the rest of the sentence. The best way to correct the sentence above is, "If you don't stop being so rude in your classes, you will get sent home before the end of the day."

The sentence above contains a dependent clause, a clause that cannot stand on its own as a grammatically complete sentence. "When I walked in the woods," is used as an introductory clause and thus must be separated from the rest of the sentence. The best way to correct the sentence above is "When I walked in the woods, I saw many beautiful creatures."

In the sentence as written, the phrase "one of my favorite writers of all time" is an interrupting phrase. It should be separated from the rest of the sentence by commas. As such, there is a comma missing between "Herbert" and "one."

In the sentence above, "Whenever I get depressed" acts as an introductory phrase. It should be separated from the rest of the sentence by a comma.

Introductory or interrupting phrases (i.e. phrases that are subordinate and add information to a sentence, but are not necessary to the sentence being complete) must be separated from the rest of the sentence by commas. In the sentence above, "evening please" should read "evening, please" so that the introductory phrase is properly separated from the rest of the sentence.