"You can't celebrate this holiday." "You must go to church on this specific day." "This particular instrument is Satanic." "This music style is never acceptable." "This food is out of bounds." "You can't drink this." "You must perform this ritual." "Only people connected to this denomination are saved." "You must use this version of the Bible."
I could go on. Mankind has invented so many traditions, it has been said there are as many religions as there are people. Tragically, many of these man made traditions evolve into denominations, many of which assert their own authority to enshrine their traditions as doctrines.
A key question to ask when it comes to any tradition is "where is that in the Bible?" The Bible, you see, contains everything a Godly person will ever need (2 Timothy 3:15-17). If it's not in the Bible, it's not a Christian doctrine. If it's not a Christian doctrine, it's non-binding at best, heretical at worst.
I remember a debate I had with a man whom we'll call "The Doctor" (since he loved flashing his doctorate around as if it were a certificate of inerrancy from God Himself) on the ethics of music. My position is that all music intended to worship God is valid as worship of God. It doesn't matter what instrument you use, the tempo is irrelevant, everything up to the lyrics is amoral. Keep the lyrics clean, the song is clean.
But The Doctor insisted there was a problem that needed to be solved, and he insisted there were a number of ways to solve it. I asked him to find his views in the Bible, which of course he couldn't do, but he insisted the problem does exist because "I can see it, and Dan Lucarini can see it". To The Doctor (whom, it should be noted, actually resorted to mocking the Bible and the faith I placed in it), the word of God meant nothing; the word of man is what's important.
But Jesus says no. If you teach as doctrine the traditions of men, you are worshiping God with your mouth, but not with your heart. And this doesn't just apply to worship music. My initial paragraph listed a number of very real man-made traditions (albeit ambiguously). As a rule, with no exceptions, check your every belief against the Scriptures. If the Scriptures teach it, obedience is a requirement, not an option. If the Scriptures do not teach it, but do not necessarily oppose it, you're free to observe or abstain as you see fit, but no one else is obligated to do it your way. If the Scriptures oppose it, you need to oppose it also. Always make a clear distinction between the word of God and the word of man, because at the end of your life, it's God you will answer to.