Passover and its original meaning.
Passover, or Pesach is one of the three major festivals for the Jewish people. Today it is known as a commemoration of the Exodus- when the Jews were passed over by Yawheh because they marked their doors with ritual blood while he slayed the first born of every Egyptian family, and of the following day when the Jews were lead out of Egypt by Moses.
The origins of Passover though, come from TWO festival celebrations that the ancient Israelites practiced BEFORE the Yahweh cult came into dominance. The first pre-Yahweh celebration would have been for the first harvests of the growing season; the second for the births of the first lambs. After the Yahweh cult took over, ancient Israelite males would travel to Jerusalem to offer sacrifices and bask in feasts and the divine presence of Yahweh.
Pesach in ancient terms, actually meant the name of the sacrifice of something, NOT the passing over of something. Pasach means to "pass over" and serves as the root word. However the actual meaning for Pesach appears to have been something akin to "To stand guard over"
Most modern scholars are in agreement that the ceremony for unleavened bread, as well as the sacrifice of a lamb were both used well before the supposed Exodus. Moreover, most scholars are in agreement that both ceremonies were separate entities. It's also almost a certain probability that not ALL the tribes were "lead out of Egypt" because the archaeological, genetic evidence, and written history not part of the hebrew bible shows that some ancient Israelites stayed in the Palestine area.
Given the story the Jews remember of the apparent Exodus, and the historical evidence, that Pesach originally served as a community building and strengthening ceremony. The quality of the food would be better, because it was a sacred ceremony, and the ritual of marking ones door with blood could have represented who participated in the ceremony.