A few observations:

1. The world moves on. In history people suffered terrible tragedies - the Titanic, the Hindenburg, Mt St Helens etc., and terrible wars. They said "We'll never forget." But life keeps going and memories fade and the immediate passions dull into old griefs. 9/11 can't be any different.

2. Bad and good don't cancel each other out. None of the bad that's happened "in the name of" 9/11 or as a consequence of it in any way undoes the heroism, sacrifice, or achievement of that time and what followed.

3. Most people who have been through a remarkable time in their lives - and warfare certainly counts - tend to either latch onto those defining moments and relive them for the rest of their days or else allow bitterness to tarnish their memories. Old soldiers here in the UK still say "We didn't fight World War 2 / Suez / Korea / Falklands etc. for the country to become like this." The reactions are understandable, but the reactions need to be seperated out between natural emotional feelings and genuine contemporary concern.

4. The day and its commemoration may not have much emotional resonance to you anymore, but the changes it wrought upon you are still evident, and in some ways remaining true to the lessons you learned at that time is actually a better way of commemorating what happened than a once-a-yuear ceremony.