I wrote a bit on Good Friday last year that I don't think I could say any better this year:
Sacrifice is a common theme among world religions.
The Greeks and the Romans were perfectly familiar with the concept of a son of a deity walking around on earth; part of the reason Pilate freaked out when the Jews said Jesus claimed to be the Son of God. Pilate, a Roman who no doubt worshiped Zeus and Mercury and the like, had no problems with the notion that the Son of God could be standing before him. So the idea of God coming down to walk around with people isn't unique either.
But...God sacrificing Himself on behalf of the people He loves is unique.
All other religions require people to sacrifice to appease God. Christianity states that God sacrificed himself so that sin could be removed and His relationship to people restored.
Good Friday is dark and grim and shocking ... Resurrection Sunday is the miraculous fulfillment, and together they are the difference that makes Christianity unique.
Actually, Good Friday is the culmination of the Great Sacrifice; the first was Jesus leaving heaven, leaving glory, to come walk around on earth as a human, subject to all the same stuff, the same vulnerabilities as every other human.
That He also endured Good Friday for us...not just the unspeakable physical suffering, but the emotional suffering of being rejected by the very nation He had come to redeem, abandoned by nearly all the people who were close to Him and under the judgment of God for transgressions He did not commit...(my rebellion and my selfishness) ...is further evidence of His amazing love for us.
Inspired by the BSF study of John, May 1996: