Recently I asked a question about articles. Since I did not understand that case clearly I continued on this topic and have a couple of another questions why authors (native English speakers) used 'a' over 'the'.
- A person says:
Next summer, I'll be on a island, with your girlfriend, and a pocket full of numbers.
Why did he say 'a pocket' if it's obvious he was talking about his pocket?
- Another person says:
I'm riding with a friend that is high as me
Why did he say 'a friend' if the situation occurred in the car in which there were nobody except them 2.
P.S. Actually, the words 'girlfriend' and 'friend' were replaced over strong language.