Suggest you read "Operation Double Cross: The True Story of the D-Day Spies" - Ben Macintyre. "Churchills Heroes" by Nicholas Rankin gives the wider picture including WW1.
Both books reinforce the thinking that amongst their other qualities the British are very good at being sneaky, devious...
Fortunately none of my family, althought involved to a greater or lesser degree in both World Wars, were lost. Both Grandfather and his dad served in WWI, both had close shaves but lived to tell tale. My dad was called up toward the end of the War but too late to be involved in anything more...
A bit harsh I feel. The 60th (I think) celebrations focussed on an elderly French gent who had escaped from France, joined the Merchant Navy then trained as a Commando. He and his comrades landed on the Normandy beaches singing the Mareseille. He survived, spent the rest of his life working...
I am particularly fascinated by what we would now call the "Geek" element of D-Day and the thought that the war was also "fought" far from the "sharp end" by what would then have been "boffins" or "backroom boys". Bletchley Park is probably the best known example, have yet to visit there but...