The answer is in the question. Sacred things are those who bear sentimental value.
You know something is sacred for you when it hurts you when that thing is hurt.
One must realize that sentiments are subjective by nature. If they blame your Teacher, and it hurts you, you have developed an attachment to your image of Her. If you really know your teacher’s worth, you don’t have to defend Her, and the bad things they bring about Her can’t ever penetrate your soul.
So yes, there are sacred things, not necessarily by their own worth but by our attachment. The clue is feeling hurt., if you feel that, be sure that your knowledge of that thing you hold sacred is still lacking.
This, if we dwell on mine versus others’ sacred thing. But there can arise situations when you really discover something sacred, not by your sentimental clinging relation to it, but by another feeling, that of being grateful. When you have found something higher, deeper, more alive, more beautiful, and you realize how much you receive from It, when you have a real epiphany of something really great, than you will not bother with naysayers. So indeed, one must carefully analyze if That Sacred Thing is sacred to me as my posession, as an attachment to an image of god, ultimately something of my creation, or it is an experienced gift of God.
So let’s settle with this: there are many sacred things, one’s we often would kill for. But the really sacred things we’d never kill for, but rather, die for, and here lies the difference.