Difference between 'for me' and 'to me'

[Daemon99]

"I can see it in your eyes. That you despise the same old lines
You heard the night before. And though it's just a line to you
For me it's true. And never seemed so right before "

These are the lines I picked from a song.

My question is, why is it 'to' when they say 'line to you' and 'for' when they say 'For me it's true'?

1) What good does cabbage do to you?
2) What good does cabbage do for you?

Also, can some one please tell me which one of the lines above is correct? If both are correct, what does each of them mean? If neither is correct, what is the correct way of putting it?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Nessie]

I personally think that both are correct. "To" and "for" are often used synonymously...
Anyway, let's wait for the others' idea
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... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Daemon99]

Can some one please answer this for me?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Ched133]

English prepositions are very tricky but I'm going to try

"For" means belong to something
"To" is often used for expressing a direction or motion toward something

when "do" is used, i always use "for" as the preposition

"what can i do for you" and never "what can i do to you"

what can i do TO you sounds very violent, like you are going to do something bad to that person

You need to look at the verb used in order to determine which is the most suitable

In regards to your question, i would always use "What good does a cabbage do for you?" because you are talking about what something can do for you and not what something can do to you.

But Nessie is right about these two are often being used synonymously