There is a very interesting thing about the way we count the Omer. The natural way of counting towards an event is by counting down. When one looks forward to a significant day, one counts off the days remaining between the present and that day. In contrast, when we count the Omer, we count the days that have elapsed from Pesach. Why is this so? Surely we should be counting the days remaining until Shavuos?
Similarly, we call the count "Sefirat ha'Omer", referring to the Korban Omer which is brought on Pesach. Why is the Mitzva named for the point of departure instead of the goal?
The idea that emerges is that the counting is not a sentimental marking of the passage of time until the goal; it is the building of that goal. Counting is work. Counting means accounting for and developing each component of a process fully, responsibly, and in current sequence. Only when each detail is painstakingly created and assembled into the process, can the goal be reached - in fact, that itself is the goal; the sequence is our responsibility and if it is done correctly, the goal results. The goal itself in spiritual terms, cannot be built or achieved directly - it is transcendent. But the finite components can be built; when that is done appropriately, the result manifests as a gift. The transcendence of Shavuos, Torah, is reached not by a single act which builds it, but by a deliberate painstaking building of each of the seven days of the seven weeks which lead to it. When that is done, Shavuos results. We work on the process, the pathway, not on the result, and the result happens of its own.
The clearest illustration of this is that the Torah commands "You shall count fifty days" and yet we count only forty-nine. Why do we not actually count the fiftieth day on Shavuos itself as the words clearly indicate? The answer is striking: we cannot count the fiftieth; it is pure transcendence, of another world entirely, beyond finite counting. It is Shavuos; the giving of the torah. We would be limiting it by assigning it a finite number. It is not an element, it is totality. We can count the forty-nine human stages; when we do so, Shavuos and transcendence arrive as a gift, as the amazing result of our attention to the fragments. In fact, we fulfill the Torah's command to count the fiftieth day by not counting it, by not limiting it to a finite number! That is the only way to reach Shavuos - to do all that we can and then allow the Kedusha to manifest.
And that is why we count from Pesach and not towards Shavuos. We cannot cause Shavuos; we can build the path. We build on the Omer, on what we have as a beginning at Pesach. That is our focus: "Today is one day of the Omer" - we have built one day; "today is two days of the Omer" - we have built two days. When we have built forty nine days correctly Shavuos takes over! And then we and our counting become a higher reality.
Counting days, creating time. We should not be passively riding time; we should be building our lives, causing time to become real. Passively drifting through time allows time inexorably to dissolve life; building life by building its elements consciously and actively in Kedusha, causes time to transcend into eternity.