Rather the Napoleonic War than the others, tbh.

WW1 had the trench and underground warfare, traumatizing and shell-shocking people: the first use of modern war rules. Vietnam; torture, paranoia, fighting an invisible enemy in the jungle. WW2 is obviously bad no matter where you fought, so no. Absolutely no.

With the Napoleonic Wars, you'd have to make clear which one since there were multiple ones: and the French were victorious in many. The Russian one leaves you the nice opportunity of falling asleep and quietly freezing to death. Rather painless.

And it'd be easier to desert than in the other ones. Since Napoleon did it himself many times.