Or more cynically, things only go smoothly when there's nothing at stake.
It's the other way around. The thing that's at stake is economic cooperation, so both sides are more willing to find an amicable solution than otherwise.
World peace will happen when everyone in the world [1] will be convinced that every other human out there is worth more to them alive, unharmed and happy.
[1] Or at least an overwhelming majority of people.
Not to mention peace! War is expensive, deadly, and altogether unpleasant. It's good to know this gets higher priority than minor territorial changes.
France and Belgium are within the Schengen Area and the sign out front says 81 years since the last Blitzkrieg.
This is really small potatoes.
That's what they said before ww1
I think that's only the case because this a really insignificant amount of land, nothing is "at-stake", both countries belong to the EU, and most importantly the "real" border is a line on a map that both countries agree on.