In previous years, we mentioned (here) the importance of having a proper outlook on all mitzvah performance. The point can be elaborated, as well as applied more specifically.
Rav Moshe Feinstein points out that the phrase "zos chukas ha'Torah," this is the chok (decree) of the Torah, appears twice in two consecutive parshios. This week's parsha begins with the mitzvah of parah adumah, labelled as "chukas ha'Torah," and then the requirement to purify the utensils acquired from Midian is also referred to as "chukas ha'Torah." Rav Moshe explains that the Torah equates these two mitzvos to teach that one must perform the understandable mitzvos, such as purifying the non-Kosher vessels of Midian, with the same hachna'ah (submission) as he would perform the incomprehensible chukim.
Rav Simcha Bunim of P'shischa (quoted in Otzar Chaim) notes that according to the Medrash quoted by Rashi, the umos ha'olam will ask "ma ta'am yesh bo," literally translated as a question attacking the reason for parah adumah. But the word ta'am, translated as reason, can also refer to taste. In other words, what taste does this mitzvah have; what's the physical enjoyment? They cannot appreciate the spiritual value of mitzvos, they only seek the immediate gratification. For this reason, at the End of Days, when the umos ha'olam will ask Hashem for a mitzvah and he offers the mitzvah of sukkah, they will at first be able to perform the mitzvah without any problems. However, as soon as the mitzvah become physically unpleasant, they will kick the sukkah and go inside (see Avodah Zara 3a). The non-Jews can perform mitzvos, but only if they "make sense."
Rav Soloveitchik (as quoted in the brand new Thinking Aloud on Bamidbar, by the Holtzer family) cites the final Rambam in Sefer Avodah where he offers a philosophical thought, as he often does when concluding a volume of his magnum opus.
ראוי לאדם להתבונן במשפטי התורה הקדושה ולידע סוף ענינם כפי כחו. ודבר שלא ימצא לו טעם ולא ידע לו עילה אל יהי קל בעיניו ולא יהרוס לעלות אל ה' פן יפרוץ בו. ולא תהא מחשבתו בו כמחשבתו בשאר דברי החול. בוא וראה כמה החמירה תורה במעילה. ומה אם עצים ואבנים ועפר ואפר כיון שנקרא שם אדון העולם עליהם בדברים בלבד נתקדשו וכל הנוהג בהן מנהג חול מעל בה ואפילו היה שוגג צריך כפרה. קל וחומר למצוה שחקק לנו הקב"ה שלא יבעט האדם בהן מפני שלא ידע טעמן
(Loosely translated) A person should contemplate the laws of the Torah and understand them to the best of his ability. However, something he cannot rationally explain should not be treated lightly, and cause a rebellion against Hashem. His thoughts should not be comparable to those of divrei chol. When a physical object becomes infused with sanctity, it becomes subject to severe punishment for violating that sanctity (me'ilah). All the more so one should not cheapen the holiness of mitzvos, infused with sanctity by G-d Himself.
Rav Soloveitchik explains that the Rambam is warning against trying to find "divrei chol," contemporary secular value, in mitzvos. While Shabbos and taharas ha'mishpacha may enhance one's psychological well-being and marriage, we do the mitzvos as Hashem's requirements, not as the latest forms of self-help. "Any attempt to inject contemporary meaning, which should be in agreement with the morality and the value systems of the pagan New York Times, is sinful...." We must be proud and confident in our observance of all 613 mitzvos, and not feel desperate to find contemporary cultural value and public approval in all that we do.