Sometimes I feel like Gary Sinise in Forrest Gump when he talks about his ancestors fighting and dying in every American war.
In tracing my scattered extended family, I've found them popping up not only in both World Wars, but in Korea, Vietnam (US and Australian armies), Sudan, Crimea, American Civil War (both sides), Boer Wars (both sides), various engagements in India...
...and randomly enough, the Franco-Prussian War, because apparently the British Empire wasn't having enough wars, but Otto Bismarck was hiring.
The ones I can't get over are the emigrants in the US who, in 1914, raced up north to join the Canadian Expeditionary Force.
It seems to be in the genes.