When I was studying Greek in school, we read Xenophon's Anabasis. One of the things I remember from the class was an illustration in the book of some ancient spearheads which had "ΔΕΞΑΙ" engraved on them. It's an imperative of a word which means "to accept".
If that hasn't struck you yet, the imperative of that word would basically boil down to "take this!".
On a spear head, I don't know whether to think it's funny or not. It seems a bit like pilots painting hash marks or naked women on their planes in an attempt to lighten their situation. The fact that this bit of "humor" is thousands of years old struck me, because I could picture people today doing something similar. It's no big surprise that people were people, but it somehow made them more real to me.