Some of the most fundamental mitzvoth of the Torah are stated in the vaguest of terms, with few clear guidelines as to how they are to be fulfilled. The central mitzvah of Sefer Vayikra, and perhaps of the entire Torah, is to "be holy", yet the meaning of holiness is left undefined. One will not find any Talmudic discussion of the laws of holiness. The closest we get to such is Maimonides' inclusion of the "Book of Holiness" in his Mishnah Torah, which details the laws of kashrut and forbidden relations.
Similarly, the command to do the "straight and good" (Devarim 6:18) is purposely vague, encompassing as it does our relationship to our fellow man. Even such crucial mitzvoth as honouring our parents, loving our neighbour as ourselves, and the mitzvah to believe in G-d are not clearly defined-and are, in many ways, undefinable. The Rambam's definition of belief in G-d differs from, say, that of the Abarbanel.
Yet we have other mitzvoth in which each and every aspect of the mitzvah is spelled out in exacting detail. Take korbanot, sacrifices. The Torah goes into detail after detail - what type of animal, when it is to be brought, who can slaughter the animal, how the blood is collected, where and how it is sprinkled, how old the animal must be, and on and on. And in almost every situation, a minor variation renders the sacrifice invalid. We are even told which thoughts invalidate the sacrifice, something that is found in no other mitzvah.
The fifth chapter of Mashechet Pesachim opens with the laws of the korban pesach, a discussion that lasts five chapters and over 40 pages. The Mishnah discusses the appropriate time of day for the korban pesach to be slaughtered, on weekdays, Fridays, and Shabbat. We come across detailed discussions of how to procure the animal, sacrifice it, and prepare it for the seder, where it can be eaten, and who may-or may not-eat it.
Jewish law demands great precision, and attention to the minutest of details. In the technological age in which we live, this should be easy to appreciate. The smallest of glitches can wreak havoc on a computer system, a slight change in research conditions can invalidate an experiment, and success in life is often measured by inches or hundredths of seconds. Exacting and uncompromising conditions are the necessary ingredients for greatness. Research and development in any scientific field is, at times, tedious, repetitive, and very detailed, requiring long hours and great effort. Such work is generally carried on in obscurity, with little recognition or material gain.
In Torah, we toil in a manner that is not that much different. It is done lishma, to carry out the will of G-d and to discover insight into G-d's Torah and creation.
Yet, at the same time, Torah requires great flexibility, attention to changing social conditions, and fluidity, enabling it to shape the contours of the discussion on contemporary topics. It requires that we know how to use that all-important "fifth section" of the code of Jewish law, common sense. Torah is meant to be transmitted primarily orally, and no two oral teachings can be exactly the same. The written word had a finality that our tradition wanted to (but could not) avoid.
Generally, it is in the realm of mitzvoth between man and G-d where detail is crucial. G-d is unchanging, and serving Him must be done with great care. It is in the realm of mitzvoth between man and man where many mitzvoth are expressed in general terms. Man is a complex, inconsistent, constantly changing being, and our relationship to man must reflect this reality. What for one may be a demonstration of love, for others may be a needless intrusion.
Pesach reflects both these notions. The detailed laws of ensuring a kosher Pesach can be mind-boggling. Yet Pesach is ultimately about freedom, responsibility, community, and family. And for each of these, there are different models.
We must not lose the forest for the trees, while ensuring that we care for each and every one of those trees.
 If erev Pesach falls on a Friday, the broiling of the korban must be done before Shabbat, a consideration absent in other years.