The table is set, and we are ready to eat. The sources simply say "one eats whatever one wishes, and drinks whatever one wishes". There are no halachic requirements for the meal, nor even universally accepted customs. The only one that comes close to being universal, is that we first eat of the egg on the seder plate, which is in memory of the "hagigah", the holiday offering, dipped in the salt water (or vinegar) that had been used to dip the 'karpas". Of course more eggs are added so as to have enough for everybody. As there is no way to mistake an egg for an actual sacrifice, there is no objection to eating it. Some serve it whole, others chop it up. Every Jewish community has its own customs of "must have" foods, but none of these are anything near universal. There are, however, huge differences between Sepharadim and Ashkenazim. For Sepharadim, this meal, and every other meal during Passover, doesn't look very different from a normal Shabbat or holiday meal. As we Sepharadim do not have the numerous strictures about legumes, or other foods that do not contain the forbidden grains, but became "forbidden" by local custom, the only observable difference will be the substitution of matzah for the bread. (Sadly, in recent times, many Sepharadic communities have adopted some, or all, Ashkenazic ways). Some Sepharadim do not even use special eating utensils for Passover, reserving that for cooking utensils only. Others use glass utensils that they use all year long, merely rinsing them off for Passover. Also, Sepharadim understand the concerns of not looking as though we are eating the Passover sacrifice to refer only to the eating of a lamb that has been roasted whole, the way the sacrifice was. Ashkenazim, on the other hand, avoid any kind of grain, most seeds,and many vegetables with crevices that could possible hide hametz (asparagus, mushrooms, and a host of others). Many avoid vegetables that normally grow next to grain. For this reason, Russian Jews do not eat garlic on Passover, a custom unknown even to other Ashkenazim.There are many other examples. The avoidance of anything which might look like the sacrifice is strictly observed. In most devout homes, the main course is boiled chicken Chickens were not used in any sacrifice, and the Passover sacrifice especially had to be roasted. I must admit that I do not fancy boiled chicken, and back when I was an Ashkenazi, this, for me, was the hardest part of Passover; indeed, of being Jewish in general. The actual rule for Ashkenazim, however, is to allow any meat that has been braised or fried, rather than roasted. Many more liberal families will follow this. Another East European, especially Hassidic, feature of Passover is the non-eating of "gebruchs", that is, matzah that has become wet. (That's right, no matzah balls, matzah brei, or anything containing matzah meal). This was based on a fear that perhaps the matzah somehow got some raw flour onto it, which will become hametz when exposed to water. This is regarded by most as an overly extreme stringency. It is reported that the Vilna Gaon, the great opponent of Hassidism, kept matzah balls in his window, in order to show his opposition to this custom. Even Rabbi Nachman instructed his followers not to to take this on, if it was not already in their family. Nevertheless, should you visit most Hassidic homes, you will see the matzah wrapped in cloth or plastic, broken off and eaten away from the table. It is difficult (at least in the U.S.) to find Kosher for Passover cakes not made with the ubiquitous potato starch. (Fortunately for the Ashkenazim, the view of a prominent turn of the Eighteenth century rabbi, that potatoes are also forbidden, has not been accepted.). Some Ashkenazi families will not consume for Passover anything that they, themselves, did not prepare from scratch. Those who keep all of these customs, regard being extremely careful as pleasing to G-d. Those who do not, regard it as violating the Torah command of "rejoice in your festival". (I'm with the latter, but many would disagree). In any case, being festive, observing the Biblical and Rabbinical commands, and being grateful to G-d, is at the heart of all Passover observances.