You may not have heard of the small country of Lichtenstein, a tiny country in central Europe which is landlocked by Germany, Switzerland, and Austria. It is a microstate, and still has a constitutional monarchy with the Prince of Liechtenstein at the top.
But that didn’t stop Switzerland accidentally invading the little country three whole times!
The first blunder happened in 1985, when the Swiss army was performing several artillery exercises. Somehow someone miscalculated the trajectory of various rockets and they ended up bombarding Lichtenstein by error. Luckily there were no casualties, but had they have landed in a village this story would be a lot worse.
On the second occasion in 1992, the Swiss military crossed the border into Triesenberg because they actually believed the village was still in Switzerland. Some may call this a small error, but not knowing what is your country when it comes to national defense seems like quite a big error in retrospect.
Then fifteen years later, they did it again. The Swiss army has to be very bad at reading directions or very bored of being neutral. As once again they marched a whole mile into the principality of Liechtenstein, only to realize they once again were going the wrong way.
Only about 37,000 people live there and the country is only 62 square miles, economical speaking it is very strong with an unemployment rate of only 1.5%. It has had a bad name of being a tax haven for billionaires, however, recently it is no longer on countries blacklist for being uncooperative when it came to investigations. Maybe the Swiss army just wanted to check their banks? Though that seems odd as they do share a customs and monetary union with Switzerland.
The only explanation here is errors in judgment or just that the soldiers were in fact bored.