memorize a poem

My favorite of hers is:
“The doorkeeper has feet seven fathoms long,
and his sandals are made from five ox-hides;
it took ten cobblers to fashion them.”

But I don’t think I’m going to do that one. The problem with Sappho and other Greek Lyric poets is that all the poetry is in fragments. So if I just memorize a fragment is it okay, since nobody knows if there’s more to it or not? Let’s say it is okay. In which case, I will do this one by Sappho:
“The moon has set,
and the Pleiades; it is
midnight, and time passing;
and I lie alone.”

That one’s kind of depressing though. I like the first one better. Maybe I’ll keep looking.
Opinions, anyone? Favorite poems? Suggestions?

the only one i know is:
“i’ve never seen a purple cow
i never hope to see one
but i can tell you anyhow,
i’d rather see than be one”
i need to learn a real one.