Very common!

i) Who do you think he is singing to?

r: I think that could be both of them but in my personal opinion, men generally tends to get bored easily so in this particular case I think that is him who wants to go away. He is fed up with her and with the relationship in general. He needs some time alone, perhaps he needs to miss her. There are some many reasons.

ii) What does he think of this person?

r: Well he says that she always believe she is right even when she is not, also said that he hates some things she does, the way that she says the things, he doesn't like the music she listens or the books she reads. He is tired of the relationship.

iii) What phrases tell you this?

r: I hate the way that you are so sarcastic or I hate the books you read and all your friends.
Also phrases such as I hate the way that even though you know you're wrong you say you're right or Your music's shite it keeps me up all night.
It seems that he doesn't want to see her again, but he says he will be back but he needs to be alone for a while.

iiii) Does he still feel the same at the end of the song?

r: Yes he still saying the things he hates about her but he is sure that he will come back.
Perhaps he knows that he will never find another love like her despite everything.