Ōdī et amō. Quārē id faciam fortasse requīris. Nesciŏ, sed fierī sentiō et excrucior. I hate and I love. Why I should do this, perhaps you may ask... I know not, but I feel it done to me, and I am wracked.
Written after he broke up with Lesbia. Yes it is very sad that I can instantly recall this after fifty odd years. Perhaps Latin really does train your brain and memory.
I remember it by heart too, from 38 years ago. Plus most of "O Sirmio, gem of islands and peninsulas, every one of which Neptune, in his dual role, supports in the liquid lakes and vast seas...".
That was thanks to a mid winter Catullus test that got delayed several times due to flu circulating in our year 11 class. By the time everyone was finally back in school, we'd revised it something like 5 times and knew all the set poems off by heart.