I want to say this, and it may just be me. If it is that is fine.
I do not think that perpetual grief and its observance is good.
It recalls the pain and the anguish without any effort to move past the long ago moment. At some point we really do need to put the past behind us.
That said, if we want to commemorate the bravery exhibited on Flight 93 or by the first responders that without regard for their own safety ran up those stairwells to their death, then we should do so. But, let's not honor them with shows of grief or sadness, but let's honor them in ways that seek to lift our spirits and encourages us to emulate their bravery if and when the need arises.
Let us honor their courage more than mourn their loss.
For those with personal losses, it is entirely appropriate to remember the sadness of that day. It is not those to which I refer.