Chazal tell us, "After the destruction of the Bais Hamikdosh, each day carries with it more curse than the previous day. [If so] on what [merit] does the world exist? On the "kedusha d'sidra" and the "amen yehei shmei raba" that is recited after the study of aggada. As the pasuk says, 'The land that's darkness is like pitch blackness; a shadow of death without order'. [However,] if there is order, it will light up the darkness" (Sotah 49a).
Rav Wolbe (Alei Shur vol. II pg. 321) explains that when the Bais Hamikdosh stood there was an abundance of blessing that permeated the world. Once it was destroyed, Hashem "hid" Himself and sealed the wellsprings of bounty, thereby leaving us in the dark. The blackness that pervades all aspects of this world - be it in the political, financial, or spiritual arena - gets darker every day. We no longer have the sacrifices that brought the world closer to Hashem and opened the conduits of blessing. If so, wondered Chazal, what gives the world its energy to continue to exist? They searched and found two small sedarim that serve as a worthy merit: the "kedusha d'sidra" and the "amen yehei shmei raba" which is recited after the study of aggada. Rashi explains that kedusha d'sidra refers to the seder of kedusha (in U'va L'tzion) that was initiated so that the entire Jewish Nation should recite at least a small portion of Torah every single day. This, coupled with the "amen yehei shmei raba" that was recited week in and week out each Shabbos after the aggadic discourse, give the world the ability to continue. The golden rule is that if there is seder, it will light up the darkness.
When one follows a schedule during his day, he feels satisfaction that he has had a fulfilling day. This is not so when his day lacks any semblance of schedule. He climbs into bed with a sense of disappointment: "Could this be considered a productive day"? If you encounter someone who is confused - unsure of himself and his aspirations, busy with insignificant things and seeing no future for himself - check to see if he has any schedule in his daily life. A lack of seder brings along with it a lack of desire; so it is no wonder that he gropes around in darkness to find himself.
If we have been acting in accordance with the guidance given the past few weeks, we should have already established a basic outline of how we want our weekdays to look. Now, writes Rav Wolbe, we should make some sort of seder for the days of Shabbos and Yom Tov. These holiest days often pass not only without spiritual growth, but also with an abundance of wasted time. Our agenda should include an ample amount of time for resting, but we must not forget to allocate time for spiritual endeavors. If we do this, we might merit "tasting" Shabbos. For as we proclaim in the Shabbos mussaf, "Those who 'taste' it - earn life."
(A sefer that deals with the halachos or hashkafos of Shabbos or of a specific Yom Tov, can do wonders in enhancing a Shabbos/Yom Tov experience.)