In ten days from now we will standing in Shul at the pinnacle of Tefila of the year, Musaf of Rosh HaShanah. And what will we be saying with tremendous Kavana? None other than Aleinu L'Shabeiach! Yes, the tefila that ends every davening, which we usually say when we are physically or mentally halfway out the door.
Rav Hai Gaon writes that Aleinu should be said with your head covered because the praise of Aleinu to our Creator is unequalled among all other praises and is the greatest praise in the world. The Rokei'ach writes that Aleinu is the Shir HaShirim, the song of all songs and we should concentrate with our whole being when singing it to Hashem, for it is "Mifuar, uMihudar, uMiutar, uMikudash, uMirumam" glorious, beautiful, the crowning jewel, holy, and elevated. The Mishna Brura says that when we say Aleinu, Hashem stands with His entire Heavenly entourage and answer Ashrei Ha'am.." fortunate are the people!
A look into the history of each nation and each people will reveal that they were each built on corruption and immoral pursuits and ideals. Proof of this is each nation's ultimate demise. Their rotted foundation crumbled and left a pile of rubble with not enough true substance to recover and rebuild. A deeper understanding of history will make you feel truly privileged to be Jew, a servant of Hashem and an adherent to His Torah.
In Europe during the Holocaust there were Yeshivos who danced to their killing field carrying their Sefer Torah and singing Aleinu. Even as they were being marched out to their death by their bloodthirsty tormentors they felt like they were the fortunate and victorious nation.
The Ramban says our laxness in the way we say Aleihu is a prime example of what Chazal say that "Kol HaMikudash MeiChaveiro" anything that is holier than his friend, "Charev Yoseir MeiChaveiro" is destroyed more than his friend.
On Rosh HaShanah we will all daven with great Kavana and say every syllable of Aleinu with deep feeling. But what about today and what about Erev Rosh HaShanah, and even Maariv Rosh HaShanah night? If we disappoint the Malachim the entire year, three times a day, can we really expect them to show up and be impressed when we wake up on Rosh HaShanah? If we wake up a minute before it is too late, our Rosh HaShanah can be completely different.