A particularly strange halacha exists that requires us to eat on Erev Yom Kippur. Most laws pertaining to the actual day of Yom Kippur might be difficult to do, but at least they make almost immediate sense. We understand these laws, and we can relate to them. Knowing full well what the day of Yom Kippur is we would expect to pray, meditate, spend time doing serious introspection. We would additionally expect to fast, even, and to take out the sifrei Torah and hold them close.
To have a law, though, that specifically mandates eating before all of this begins is strange to say the least, and is seemingly quite difficult to relate to. To make things even stranger, we are told by Chazal that if we do, indeed, eat on the day preceding Yom Kippur it is as if we fasted on both that day and on Yom Kippur itself! How does this make any sense at all? It is quite literally the very opposite of the reality.