Let's put this in perspective.
How many U.S. citizens have been injured or killed in a terrorist attack over the last 20 years? To cite just one year, in 2011 the number was 17 but that includes Afghanistan and Iraq and other war zones, out of the millions and millions who travel abroad each year. Compare that, say, to the over 300 people killed in gun violence in Baltimore so far this year; or the number of pedestrians hurt or killed crossing the street in New York City each month. Or the nearly 4,000 people who die in accidental drownings in the U.S. each year.
Drivers killed 10 pedestrians and cyclists in New York City in June, 2015 alone and yet I don't hear the State Department warning people not to travel to New York or Baltimore.
Yes, there is real danger when U.S. citizens travel abroad. Pick pockets are a real threat. When walking in Britain or any country where they drive on the "wrong" side of the road, Americans need to be extra careful crossing the street. Especially, do not text and walk, please. It's dangerous.
Have the recent terrorist incidents overseas made you change your travel plans? Will changing them encourage more of these attacks?