No. Apparently not. The relevance of Past perfect lies in the fact that it differentiates between the time frame of two events, when both of them happened in the past.
Example:
Before she left for her college, she had finished her lunch.
You can use After
too. In the given sentence in your question,
Mario had already arrived home when his mother walked in.
it is understandable that Mario had reached home before his mother walked in.
BUT a simple,
Mario had arrived home.
is meaningless and unnecessary as you are not referencing before what event had he arrive home. You can use simple past here. Of course, if in a conversation it is relevant that you did it before some action you can use simple perfect like you cited. Like:
2nd friend: Where do you work now?
1st friend: I work in ABC company now-a-days.
2nd friend: Oh! I see. I had worked there. (It means he had worked there before he left that job)
So put it simply,
Past perfect is not used unless and until we are comparing the time frames between two events. You can read more on past perfect in English Page: Past Perfect Tense.
I am an American, and had not noticed this phenomenon. I would have said "I was almost done with my essay when the computer crashed and I found that I had forgotten to save it". So, I decided to check a few N-grams to try to isolate it.
he had decided , he decided (American)
he had decided , he decided (British)
I had forgotten, I forgot (American)
I had forgotten, I forgot (Brithish)
she had lost, she lost (American)
she had lost, she lost (British)
From this data we can see that:
- Simple past is used more than past perfect in books.
- The simple past is used slightly less often in British books than American books.
- It varies widely depending on the verb.
This may depend on the verb in question, but we can expect to read the simple past two to four times as often as the perfect past.
I would assume that spoken English is even more biased towards the simple past than written English.
I would hypothesize that this phenomenon is due at least some of the following factors:
- For many verbs the "past" is easier or more natural to recall than the "past participle".
- Using "had" plus the past participle may add two or more syllables compared to the simple past. It is common in spoken English to use contractions and merge words together.
- A general laziness in speech.
Best Answer
One of the uses of past perfect is to refer to an event that takes place before another event in the past. For example:
The last example above is similar to the one in your example:
The event of "forgetting" takes places before the arrival of your guests, and the arrival of your guests happened some time in the past.
UPDATE
GregD points out in the comments that the situation described by the sentence:
is unlikely. I agree with him and I think that a more plausible situation would be:
In this case, GregD uses simple past to describe a sequence of events in the past. The order in which these events take place is inferred from the meaning of the sentence. It is also possible to use the past perfect to make apparent what this order is: