The Declaration of Independence did not spark any hostility because by the time Thomas Jefferson wrote it and it was sign in the fourth of July in 1776, all the colony's representatives were in agreement. However, the Continental Congress was very tense when independence came into question. When British troops attacked Concord, there was no choice but to decide what was next and after hostility occurred here, the congress voted to stay loyal but King George III said that their congress was illegal and all involved could be hanged so eventually the colonists agreed to be independent. So to simply answer your question, the colonists did face hostility while deciding if they should be independent or stay loyal to Britain, but the Declaration of Independence signed when the colonists were in agreement so there wasn't any hostility between them at that point.
The effects of the terrorist attacks of 11 September 2001 can be analyzed in three areas of approach.
1) The worst effect of the attacks was the loss of human life. In the attacks, approximately 3,000 people died, who were fulfilling their daily routine in their works, being an immeasurable loss.
2) The economic effect in the US and in the world. The attacks toppled the twin towers of New York, the nation's financial center, directly engaging businesses established there and indirectly across the rest of the country. Stock markets plummeted, jobs were reduced and the impact on GDP was significant. As the world's largest economy, everything that happens in the United States is reflected in the world. Instability has hit all stock exchanges, affecting many businesses and companies around the world.
3) Effect on national sovereignty and the escalation of the fight against terrorism. The September 11 bombing was a turning point in the terrorist escalation, making it the first time the United States was the victim of a major terrorist attack. Capturing and penalizing those responsible was a matter of honor to the country and this only happened in 2011 when Osama Bin Laden was assassinated in Pakistan. Finally, terrorist attacks began to be more frequent in Europe. The US defense system has successfully prevented the protection of the country.