What was the sermon about at your church yesterday?
Have you heard it before?
How many times has that sermon been repeated?
At the last service I attended (which was last week, on Wednesday, Christmas on the Julian calendar), at a Russian Orthodox Church Outside Russia parish, there was beautiful singing by the choir, and the Archimandrites (senior hieromonk, or monastic priest; bishops are drawn from the ranks of archimandrites) said the liturgy with great elegance, but he did not preach a sermon.
Some Orthodox priests are fantastic preachers, some aren't, some preach a sermon with every liturgy, and some do not, especially in monasteries. The liturgy itself is so full of theological information as to render a lengthy sermon redundant, especially if you attend the vigil service the night be fore the feast (or on Saturdays) or in Greek churches, Matins on Sunday morning. Matins and Vespers, which are usually served together as part of an "all night vigil" usually abbreviated to two or three hours in the Russian Tradirion, contain the bulk of the thrological information about the feast. Holy Communion does have variable parts, but most of it stays the same, and focuses on driving home the core doctrines about creation, the Trinity, the incarnation, passion and resurrection of our Lord, and the real presence of Christ in the Eucharist. The same is true of the other sacramental services like baptism, marriage, holy unction (my favorite; it's given to everyone on Wednesday of Holy Week), et cetera. So most of the time you don't need a sermon. That said there are some fantastic Orthodox preachers who can uplift you as much as the late Dr. james Kennedy, who I much admired.