An amazing Midrash says as follows:
"When the Sea covered Pharaoh's army, the Ministering Angels opened up with songs of praise to G-d. G-d said to them: The work of My hands is drowning in the Sea, and you are singing?". This is the part of the Midrash that is most often quoted. It seems to be saying that the miracles associated with the Exodus are not to be celebrated, but to be mourned, as loss of life was involved. Many rabbis gave this as the basis of pouring out some of the wine at each plague. Some commentators even pointed to other traditions, which seem to place Passover on a lower level than Shavu'ot and Sukkot; the other Pilgrimage Feasts. However, the Midrash continues: "THEY (the Angels) must not rejoice. But others, namely the Israelites, must rejoice". That is, on an ideal, Heavenly plane, there can be little joy in a deliverance that involves the destruction of human life. But on a human level, a person (or a people) being saved from death and suffering, cannot be expected to mourn for their persecutors, but must first and foremost be thankful for their own salvation. Should a Holocaust survivor feel sorry for the deaths of his Nazi oppressors? Or should their deaths be a further reason to rejoice? Therefore, in light of the rarely quoted part of the Midrash, we are confronted with two possibilities; emphasizing joy in what has been done for us, or mourning the cost. Those who see the pouring out of the wine as the wrath of G-d coming upon our foes as the operative event which we celebrate, fundamental to the theme of redemption, celebrate the event and the emotions it engenders. . On a higher plane, there may very well be cause for diminished joy. But we don't live on that plane. Here and now, there is the recognition of a great gift, which essentially begins our journey as a people. A possible analogy would be the issue of saying the "shehechiyanu" blessing at a Brit (circumcision). That blessings gives thanks to G-d for having allowed us life to celebrate joyous events. Bringing a baby into the world, and bringing him into the Covenant, is one of the greatest joys possible. The halachah is clear in our sources that "Shehechiyanu" is to be recited at a Brit. Nevertheless, Ashkenazi tradition (outside of Israel) is to refrain from pronouncing this benediction, as we are causing pain to the baby. Joy and pain are two inevitable parts of life. Many people cry at weddings. Most rejoice. Where do we put the emphasis? Back in the early '90s, with the fall of the Iron Curtain, many Jews began visiting the Nazi death camps in Poland. A group of Israeli High School students went on this "March of the Living", accompanied by the Israeli Minister of Education, a radical Leftist and Secularist. Reporters asked the students what they got out of this trip. All answered "pride at being a Jew". The Minister said "Proud?!?! You should feel humbled and ashamed!". The choice is ours.