There are some parshios that seem to have little "luck". One such parsha is Parshas Shmini, which usually follows Pesach, making it feel very anticlimactic - sort of a side note to days of such import. The beginning of the parsha, which deals with korbanos, also does not ignite much interest. But this is the most profound moment in the history of Hashem's bond with Klal Yisroel. After building the parts of the Mishkan, erecting the structure and spending seven days offering sacrifices, on the eight day the Divine Presence finally descends on the Mishkan to become a permanent presence in the Jewish nation.
The structure of this sequence of events is not seen as an "eight day" enterprise, rather it is a unit of seven days followed by an "eighth day". It is as if there are two phases needed to bring about the presence of the "Shechina".
Let us point to two parallels. First, in the classic primer for avodas Hashem, the Mesilas Yesharim, the Ramchal describes all the rungs in the ladder of avodas Hashem. At each step, he describes in detail "the rung" itself, the ways in which one acquires it, and how one stays away from pitfalls. When he comes to the last rung, i.e. kedusha, there is a remarkable change. He starts by saying that kedusha is a twofold entity; it starts with human endeavor, but ends with a Divine bestowal of that kedusha.
Second, the Rambam, in a different frame, has a very similar concept. In chapter seven of Hilchos Yesodei HaTorah he describes the development of a navi. He discusses all of the character traits that he must develop in himself, and if done properly, Ruach Hakodesh is immediately bestowed upon him (halacha 1.) However, this is still not nevuah. After further preparation he waits for the Divine Presence, which is nevuah, which may or may not happen (halacha 5.)
In both the Ramchal and Rambam we find the same structure of a person's avodas Hashem: many rungs that depend solely on man's avodah, followed by the final step which is a display of Hashem's participation [though there seems to be somewhat of a disagreement whether kedusha or nevuah is that last rung.]
The reason for this two stage reality is that it is up to a person to develop his own character and thus make himself worthy of bearing the Divine Presence. But the "Divine Presence" is the "other", and I cannot force it to come, no matter what I do.
This same dichotomy also is what distinguished the seven days from the eight day. Seven days represent the human effort to be fully mekadesh oneself, but that by itself is not the Divine Presence. The Divine Presence is marked by the acceptance of the sacrifices by Hashem, expressed as the fire coming down and consuming the sacrifices. This is analogous to when I present a gift to a loved one - I can put all of my effort into making the gift as beautiful and meaningful as possible, but it is up to the other person to accept the gift and thus "complete the circuit".
Perhaps this was the reason that Aharon was so reluctant to perform his duties, because of what he felt to be his character shortcomings [i.e. the sin of the golden calf.] Had this avodah been presented as just an obligation, he would not have resisted. After all, no one has the right to demur at doing what he is supposed to do simply because he feels he is not a big enough tzaddik! Rather, Aharon's protest was that if the goal of that day's avodah was to have Hashem accept the sacrifices and show how pleased He is with us, Aharon felt fearful that his shortcomings would interfere.
Is this second phase of kedusha / nevuah totally passive, or does it require something of us? Let us go back to the analogy of a gift to a person whose closeness we desire. It is important that gift be as nice as can be. But if I present it to the other person as a demand or imposition, i.e. "look at how I'm treating you, you have no choice but to be my friend", it is a turnoff for the other person. The most important ingredient for the gift to be accepted is an air of humility and an expression that it is my profoundest hope that you deem me fit to be close to you. One cannot "bully" his way into Hashem's presence.
The Chozeh of Lublin [also quoted in the name of the Ba'al Shem Tov] expressed this most succinctly in the words of Chazal, "Moshe told [Aharon], 'why are you embarrassed [to bring the sacrifice], for you have been chosen to do so [lekach nivcharta]'" The Chozeh reads this as, "you have been chosen for this very reason [lekach nivcharta]", i.e. your humility and lack of a sense of entitlement!
The totality of avodas Hashem thus requires of us two, almost opposite, approaches. The first is an "im ain ani li mi li" attitude, i.e. that everything stands on my, and only on my, efforts; combined with an extraordinary humility of "u'k'she'ani latzmi mah ani". Then, and only then, do we merit that the Shechina "resides on our handiwork."