Back in Ancient Egypt they had a different approach to part of their army, and it was one that was light years ahead of even where we are at this moment in time.
There was a section of their army that consisted of 150 gay couples based out of the ancient city of Thebes. The theory behind all of this was that you are more likely to fight harder and try to achieve more if you are looking to impress your lover. It is also important to point out that there were fewer restrictions and persecutions surrounding people who were gay at this time, so it was not frowned upon in society.
It is unknown as to whether or not this part of the army was successful, or if it was simply down to their fighting ability rather than their attempts to impress someone else by being the best warrior in the world.