Christmas celebrates the birth of Jesus Christ - the most important event in human history (along with the rest of Jesus' life). Even if people fail to acknowledge its meaning, that doesn't change its significance.
Why is Christ's birth so important? One reason is because of who He was: the divine Son of God. To those who witnessed His birth, He probably looked like any other newborn baby - but in reality He was far more. He was God in human form - fully man, but also fully God. Only Jesus could say, "Anyone who has seen me has seen the Father" (John 14:9). Only Jesus could say, "I and the Father are one" (John 10:30).
Do you want to know what God is like? Look at Jesus Christ, for He was God in human flesh.
But Christ's birth was also important because of what He did. He came to show us God - but more than that, He came to open the way to God. We are separated from God because of sin - but Jesus came to take away our sins. He did this by becoming the final and complete sacrifice for sin through His death on the cross.
Admittedly, Christmas for many people has become little more than a secular holiday. Don't let this happen to you. Instead, put Christ at the center of your Christmas this year - and at the center of your life.