The long and miserable history of armed conflict has seen wars kicking off for dozens of different reasons. Independence, territorial disputes, cultural differences, religion, philosophy, or just living next to each other for too long have all got presumably sane and rational people to grab the nearest killing implement and attempt to mutilate each other in the biggest numbers possible.
It seems impossible for humans to live in groups that identify as nations without wanting to start throwing hands at someone else.
There are times in history when two groups of aggressive people just couldn't be bothered to think that deeply. They really, really wanted to have a war and seized on the first available excuse to get rucking, no matter how lame or bizarre that excuse might be.
Either that, or they were so hyped up and kill-happy that all it took was some innocuous trigger event to get the tanks rolling across that border.
The wars that followed owed their existence at least partially to some very stupid reasons, which would all be hilarious if so many people hadn't died.
10. Football (El Salvador Vs. Honduras, 1969)
In the late 1960s, El Salvador and Honduras had a problem with each other. Honduras had land and El Salvador had people, so there were a lot of Salvadorians in Honduras, and Honduras was in the process of enthusiastically evicting those Salvadorians from land they occupied to give it to good, hard-working (ie rich) Hondurans.
While the underlying reasons had been bubbling noxiously away for a while, it took 'the Beautiful Game' to spark full-on bloodshed.
Qualifying for the World Cup called for a series of three football matches between the two nations. In late 1969 these matches happened to the tune of hooligans battering each other with nationalistic fury, causing tensions that could only be sated with a declaration of war.
The evening of the third match, El Salvador dissolved diplomatic ties with its neighbour and invaded a couple of weeks later. The war lasted four days, hence the nickname 'The Hundred Hours War', and a ceasefire was negotiated without anyone really achieving anything.