I read D-Day, June 6, 1944: The Climactic Battle of World War II by Stephen Ambrose back in 2001 and was stunned by it and moved by it. I came away from that book thinking about it in the days that follow more than any previous book I’d read. It described something astonishing, that I, as someone born in the early 1970s couldn’t really conceive of. I had nothing to compare it with in my own experience. Even later that year, when the World Trade Center came down, I thought of Pearl Harbor, but D-Day remained in a class by itself.

My grandfather and great uncles all served in the military during the Second World War, and I’ve heard some of their stories. I’ve read other accounts of the D-Day operation, and of course, I’ve read Band of Brothers and seen the HBO mini-series.

Sometimes, when I’m feeling particularly lazy, I think about the men who on a morning in June, 70 years ago, were ferried to the beachheads in Normandy by Higgins boats, and landed on those beaches to begin the liberation of France, and the rest of the world. For many of them, June 6, 1944 was the last day of their lives. I think about that, and it usually dispels that lazy feeling I have, but shamefully, not always.

What almost always does the trick is thinking about the 70 intervening years, and what those men who died on the beach never got to see: the Allied victory; the end of the war; their families and friends; Chuck Yeager breaking the sound barrier; the Brooklyn Dodgers “shot heard round the world” in 1951; Alan Shepard flying into space; Neil Armstrong landing on the moon; Star Wars; Stephen King; the Internet; the Beatles; the Rolling Stones; John F. Kennedy; Barack Obama.

They did something amazing, but never got to see any of that. But we did, and we did because of what they did on that June morning 70 years ago.

Usually, when I think about that, the laziness melts away, and I get to work.