9-11 is a day in most American's lives that they will never forget. It was a sad day when so many people lost their lives for a horrific act of terrorism. We all have times in our lives that are sad for us (though for some of us those days are extraordinarily traumatic). We all lose loved ones at some point that is true, but horrific tragedies can be far more painful. We mark these occasions and keep them in our memory as a tribute to these monumental points in our lives. Once we begin to heal, we can put more focus into honoring the lives that were lost as well as honoring all those who came to the aid of others.
Any act that harms others isn't a message!
Ultimately when we harm someone else (whether in a severe manner such as 9/11 or simply by being rude to the waitress) we only harm ourselves!