Consider this slice of life in 1970s New York City (in an era when 5 bombs per day went off in America over one 18-month period):
“Radical violence was so deeply woven into the fabric of 1970s America that many citizens, especially in New York and other hard-hit cities, accepted it as part of daily life.” When a bomb exploded at a Bronx movie theater on May 1, 1970, police tried to clear the building, but patrons refused to leave, demanding to see the rest of their film.
Perhaps it is just me, but I think that when terrorists plant a bomb in the theater you are in and you just stay to watch the end of the movie, the terrorists are winning.
UPDATE: Related thoughts from Mark Steyn:
The worst civilian massacre in the United Kingdom between the Second World War and the 7/7 attacks of 2005 was the Birmingham pub bombings of 1974. For good or ill, it convulsed the nation. In contrast to the now traditional response that the worst thing about an Islamic terror attack is that it might lead to a "backlash" against Muslims and the urgent priority is for everyone to pretend that they're "united" in "one love", the pub bombings led to the immediate cancellation of the city's St Patrick's Day parade, the third largest in the world, for the next decade. Twenty-one Birmingham pubgoers died that night. Now 22 people get slaughtered at a pop concert, and the public shrug it off with some candles and flowers. Eleven civilians were killed in the 1987 Enniskillen Remembrance Day massacre (a twelfth died after 13 years in a coma), and public outrage was so fierce that the Dublin parliament passed a fast-track UK extradition bill, the IRA apologized, Sinn Féin's electoral support didn't recover for 15 years, and Bono declared on stage "F**k the revolution" - which on the whole I prefer to Katy Perry saying touch the person next to you and tell her "I love you".
Please. Don't get used to these slaughters. That's when the terrorists truly win.