When Bad Things Happen to Good People
As our Sages said (Bava Kama 60): "Tribulation doesn't come to the world except for the sake of the evil-doers. And it [tribulation] only starts with tzaddikim, etc."
And to clarify the matter: It [tribulation] happens to tzaddikim in order for the evil-doers to learn a lesson.
As it says, "And your brothers, the entire House of Yisrael, will weep, etc;" they [the evil-doers] shall become afraid for and worry about their own souls, so it won't happen to them as what happened to those [the tzaddikim] as they [the evil-doers] see that Hashem will not spare anyone.
And this is a precious explanation. [V'zeh peirush yakar.]
- It provides insight into one of the reasons why bad things can happen to good people.
- Even if you don't care enough about yourself, you can still care enough about the truly righteous people as to watch your own behavior to minimize the chance of harm coming to them.

There can be some doubt as to the meaning of such silence.
Is he silent, but distressed and resentful in his heart regarding the Judgements of Hashem?
Or does he remain silent while rejoicing in his heart according to the trait of tzaddikim, who rejoice in their afflictions?
Therefore, Hashem spoke with him personally in order to make known the purity of [Aharon's] thoughts because Hashem only rests his Shechinah [on a person who is] within a state of joy.
And this terminology means that the Shechinah rested upon him [Aharon HaKohen] because of his heartfelt joy.
And with this, it became known to all that [Aharon HaKohen] experienced joy within his afflictions as per the trait of tzaddikim.
I think it also demonstrates part of the necessity of trials and one of the reasons people need to be tried and tested by God.
Aharon HaKohen was certainly on an exalted level before this occurred, but until he was actually thrown into this potentially devastating nisayon (trial), this particular level of righteousness could not completely come to fruition.
The Kli Yakar continues:
Another thing: This silence shows how he [Aharon HaKohen] was not perturbed by all the temporal events.
And certainly, he was totally "seichli" (שכלי) just as if he was one of the Heavenly beings. For from the seichel's side, a person is not taken aback by such things.
Therefore, the decreed result was that Hashem would relate to him personally without any intermediary because he [Aharon HaKohen] was made as spiritual (ruchani) as Moshe due to his [Aharon HaKohen's] silence.

It's more that Aharon HaKohen so wholly trusted in Hashem that he didn't have any emotional investment or self-interest in the outcomes because Hashem can only do Good, so Aharon HaKohen saw everything as Good by virtue of the fact that it was Hashem's Will — whatever it may be — and so it was automatically the desire of Aharon HaKohen, too.
And this is also apparently the way angels are.
In general, they have no yetzer hara, so everything is clear to them.
Thus, they never lose their composure, regardless of what Hashem does or what they themselves are made to do.
(If anyone has a suggestion as to translation of seichel here, please feel free to leave it in the comments.)
And just to reiterate, Aharon HaKohen could not have reached Moshe Rabbeinu's level without going through this nisayon. His silence in this specific situation, which would be devastating and shocking for anyone else, and to remain silent for exactly the above reasons, were specifically what propelled him up to such an exalted spiritual level.
Using Alcoholic Beverages Non-Alcoholically

He exhorts us to never drink so much that it prevents us from being able to pray properly, including maintaining the state of mind that enables us to listen to what Hashem wants to tell us, even in the case where it is useful for consoling mourners (Eruvin 65).
He emphasizes that while it's important to use wine for Kiddush and Havdalah, one should never become drunk from it.
According to the Kli Yakar, excessive drinking leads to excessive chattering, while sober silence leads to the ability to receive Hashem speaking to you.
The Kli Yakar also adds at length that all this is in addition to the well-known problems of inebriation that lead to all the worst kinds of transgressions.
This is my own translation and any errors are also mine.