"But you are not to treat Adonai your God this way... You will not do the things the way we do them here today, where everyone does whatever in his own opinion seems right." Dvarim (Deuteronomy) 12:4,8
Adonai took the time and dedication to write out the Torah for us, for our own good, in order for us to know what to do and what not to do. In other words, the Torah (law) is our instruction manual. That is why we can't copy the practices and traditions of the rest of the world because we will end up doing something pagan and therefore forsaking our God.
If it isn't in the Bible, then better not do it. This way, we will avoid a whole world of troubles. God's way is the best and only way to follow.
Shabbat shalom and blessings to you all.
