Sorry if i'm being redudant, but
@Unnamed Namesake once wrote a very convincing post about Cana and Bacchus being an awful couple.
I can't argue about it as well as she did, and especially because i am abysmally ignorant about drinking problems. I got drunk only once in my entire life and it will never happen to me again. So i'm far from the best person to describe why Cana and Bacchus aren't a great couple, so let me try to explain what she meant back then.
She more or less said that having a drinking problem (and Cana sure has) is a big deal, and being in a relationship with someone who doens't help you stop AT ALL is the worst thing that could happen. Someone making Cana even more of an alcoholic rather than helping her stop/reduce, is a bad thing.
So yeah, she seemed to know what she was talking about and was pretty convincing to me. Which is why i didn't vote for that ship.
But ehh, any ship involving Cana is good, we get to see more of her which isn't unpleasant to me