“…[F]rom every man whose heart motivates him you shall take my portion.” (Shemot 25:2)
In order to build the Mishkan, the Torah requires, on the one hand, expensive items such as precious stones, gold and silver and, on the other hand, inexpensive items such as linen, wool, plain wood and leather. The Ohr Hachaim Hakadosh points out that if even one of these materials was missing, the building of the Mishkan could not be achieved. This doesn’t mean that each person had to donate from all of the materials, but that at the end, from everyone’s contributions, all together there had to be all of the 13 varieties. The Ohr Hachaim Hakadosh concludes that this means that we must receive from “each and every person” — without disregarding the one who brings the simple linen or leather!
Each generation has its huge talmidei chachamim, big tzaddikim and prominent saintly individuals whose sacred avodat Hashem is compared to gold and silver, their mitzvot shine like diamonds and their impeccable middot have the luster of precious stones — due to the purity of their actions and the depth of their hallowed kavanot. On the other hand, there are also the common people who fulfill and perform their mitzvot without any special enthusiasm, brilliance or splendor, and without any sacred kavanot; nevertheless, they are accepted in Heaven just as the donations of the linen, wool and leather were accepted!
Rabbi Shlomoh Bussu relates a well-known story that happened in the times of the Arizal (cited in the Sefer Mishnat Chachamim  of Harav Moshe Chagiz, zt”l).
During the Inquisition, a simple Jew who fled from Portugal came to Eretz Yisrael and settled in Tzfat. One day he heard the Rav of his shul give a drashah about the Lechem Hapanim — the special loaves that were offered to Hashem every Shabbat. As the Rav spoke, he sighed in grief and, in obvious pain, added: “Now, due to our many sins, we have no Beit Hamikdash and we are unable to offer the Lechem Hapanim.”
This Jew had never learned Torah, but he was G-d-fearing and full of strong, complete emunah peshutah. After the Rav’s drashah, he headed home and enthusiastically requested that his wife prepare two loaves of bread every Erev Shabbat from flour finely sifted through 13 sieves. Naive and idealistic, he wanted them to bake these loaves with the utmost purity and then “offer” these breads in shul. “Perhaps Hashem will accept our breads,” he explained.
Every Erev Shabbat his wife would bake the two loves, and he would lovingly bring them to shul, open the Aron Kodesh, pray and beseech Hashem to willingly accept his breads. Then he would respectfully place the loaves in the aron kodesh, and leave.
The shamash who cleaned the shul on Erev Shabbat found these breads every week and felt it was a miraculous gift from Heaven that he could bring home to his family to eat every Shabbat. He never thought to ask how it got there.
Every Friday night, the Jew who put the loaves in the aron kodesh would look inside and be filled with overwhelming joy. He would go home and, together with his wife, praise and thank Hashem for “accepting” their “offering.” Encouraged, his wife carefully continued making the loaves every Erev Shabbat.
One Erev Shabbat, the Rav was in shul when this simple Jew, unaware of the Rav’s presence, came with the two loaves of bread, opened the aron kodesh, and started enthusiastically, passionately praying to Hashem to accept his offering. When he saw this, the Rav became agitated, called the Jew over and began chastising him. “Fool! Do you think Hashem eats and drinks? Do you think Hashem takes your loaves?”
The man tried to explain that he had been doing this for months and every week the loaves disappeared. “What? The shamash surely takes them home to eat!” the Rav declared.
Then the shamash indeed came and, as usual, took the loaves.
After this reprimanding, the Jew started crying and asked the Rav to forgive him for misunderstanding the Rav’s drashah. He had assumed that it was a mitzvah to offer the loaves, but according to what the Rav was telling him, he was actually sinning!
Soon after, a messenger of the Arizal arrived and told the Rav: “The Arizal has sent me to tell you to go home and prepare your will, for tomorrow, at the time when you usually give your drashah, you will die.”
Stunned, the Rav immediately ran to the Arizal and begged for an explanation. “What did I do wrong?”
“You have caused the enjoyment of Hakadosh Baruch Hu to cease! From the day the Beit Hamikdash was destroyed, Hashem has never had as much nachat ruach as when that simple Jew wholeheartedly offered his two loaves in the aron kodesh, believing that Hashem was accepting them from him. Because of you, this man will no longer bring his offering! Thus it was decreed that you are going to die. There is absolutely no chance that this decree will be nullified!
Indeed, the Rav died the next day.
Of course, anyone who can bring gold and silver cannot exempt himself with less; and even if right now we cannot bring those exalted items, we still have to be eager and try our best to upgrade our avodat Hashem, to always try to improve the quantity and quality of our mitzvot and our kavanah in fulfilling them, to strive to achieve shleimut!
Nonetheless, we should not in any way disregard whoever has not gotten there yet! There are too many factors for us to be able to properly evaluate and calculate the real value of a mitzvah someone performs. We will never know what is really precious in the eyes of Hashem!