Let's hear it for Prepositions!
Why I was forced to memorize this crap is beyond me, but it's taking up valuable space on my cranial HD.
[list of prepositions deleted]
It could be worse: in German and Russian, you have to remember which case the object of the preposition takes. And there is a substantial number of prepositions that can take different cases depending on whether there's implied motion involved.
And then there are the verbs that take a direct object in a case other than the accusative. This is particularly bad in Russian, which has more cases than German.