I listen to a lot of dubbed anime, so I am going to modify this catagory so that I might talk a bit about bad subtitles. Bad subtitles are...bad. But, they are also really, really funny.
When I bought my copy of Gravitation, I got it for the cheaps. Little did I know that there was a reason for the bargain basement price of my copy of the series. I may, or may not, have accidentally purchased (no one sue me for this) a Hong Kong rip-off of the series. I was not aware of this until I watched it. I knew the series pretty well at this point, because Ms. Shakespeare and I had watched it together on several occasions. My copy was not like her copy. Her copy had...um...what's the opposite of word vomit?
It does not say this. It just says "Poor Sex Skill." Hahaha.
How about exhibit B?
One last one:
Tohma (whom my version insists on calling like 8 things...seriously, it's like they forgot what they named him) is lurking in the room and catches Shuichi kissing Yuki (see the Kwan there?) goodbye on the ear. Yuki gets a little flustered, so Tohma (whom my version believes is a "she," although I assure you he is not) says something like "Oh, Yuki, I didn't know you had an ear fetish." I suppose that could be a "problem," but I think it is more likely just a super bad translation.
Ms. Shakespeare couldn't even watch this version with me. She made me turn it off. I think it's hilarious. So, it gets my vote for best subtitles, on account of the amount of amusement it provides me. Not because they're good. Because they really, really aren't.