Song and dance becomes the ultimate expression of freedom, but it is not that each person sings and dances randomly. It is all very much coordinated, following the leader (himself a servant), without ego. Singing and dancing is itself a way of serving G-d. This does not mean that there is no individual self-expression. On the contrary, each person finds their full individual expression as a part of this communal song.
It is worth noting that traditional Jewish dances are done in circles. Each person dances to their heart's content, but the focus is not on the individual, but rather on the whole. (Yes, sometimes individuals enter the middle of the circle, but unless they are the bride and groom, or the bar/bat mitzvah girl or boy, or the parents, a people should check their own motivations to make sure they are dancing in the middle for the right reason, and not as part of an "ego trip").
This lesson is reflected in all of the commandments, and a proper metaphor are the very strings of the Tzit-Tzit, attached to every four-cornered garment. The Tzit-Tzit represent all the other mitzvot: part of the length of the strings are tied in knots, while the rest is let loose (the word Tzit-Tzit adds up to 600, and there are 8 strings and 5 knots, for a total of 613). Without the knots, the strings would either fall off, get all jumbled together, or worse. They would probably end up knotted anyway, just not in the way that the Torah requires. On the other hand, if the strings were completely knotted together, they probably would not even be considered strings at all, just knots.
The opening Mishna in the Tractate of Pesachim (about Passover) begins as follows: "Ohr L'Arbah Asar Bodkim Et HaChametz L'Or HaNer." This is usually translated as, "On the eve (lit. the light) of the fourteenth, we check for any leavened bread, by the light of the candle."
Fourteen stands for redemption, as it has the numerical value of the word Yad, hand, a reference to the Strong Hand of G-d that took us out of Egypt. Leavened bread, Chametz, represents a person's ego. Light is a reference to Torah, and the candle, the mitvot (the commandments), as in the verse in Proverbs: Ner Mitzvah veTorah Ohr," a mitzvah is a candle and the Torah is light.
Therefore, the Mishna can be understood on a deeper level as follows: When the light of redemption is approaching, we check ourselves for any misplaced ego, through the the light of Torah and the commandment(s). As we prepare ourselves for the final redemption and can already see the "light at the end of the tunnel," we must check ourselves for any egocentric thought, speech or deed we might have overlooked. We check ourselves by analyzing our own devotion to the Torah and to how we perform its commandments.
This devotion mentioned above does not imply, G-d forbid, abolishing our own individuality. On the contrary, it is through the Torah and its commandments that we find our ultimate self-expression. As we see in the teaching of the Ethics of our Fathers (Pirkei Avot, 6:2), "there is no free individual, except for one who is occupied with the study of Torah. And whoever occupies themselves with the study of Torah is elevated."
When Mashiach comes, it is said that the righteous will be in a circle and that Hashem Himself will be in the middle. They will all be pointing in, and saying, "This is my G-d," very much like the Song of the Sea, when we all said together: "This is My G-d and I will glorify Him." Each one will have a different perspective from which they will be pointing, but they will all be pointing in the same direction.
May it be very soon, and may we all be part of this circle, knowing what to say and what to sing, how to dance and where to point.