What is the difference between それでいい and それがいい here?


As I understand it, それでいい means 'it is fine like this' and それがいい means 'this
is fine', but what is the protagonist trying to convey here by first using
それでいい and then correcting himself to それがいい?

Background: This is the main character's internal dialogue. A girl (who
appears to be his 憧れ{あこがれ}の人 from the same school) steps onto the bus he is
on, and sparks this monologue, part of it reproduced below:

> もしかしたら違う{ちがう}世界に住んでるのかもしれない。  
>
> たまたま見えているだけで、手で触れよう{ふれよう}とすればかき消えて{きえて}しまいそうな──だから触って{さわって}はいけない、関わって{かかわって}はいけない。  
>  近寄るともままならない。  
>
> そんなバカげた妄想{もうそう}すら浮かべたく{うかべたく}なるほど、彼女の存在{そんざい}は僕にとって、いい意味で異質{いしつ}であり、遠い存在だった。  
>  僕に出来ることは、声をかけることではなく、ただただ、こうやって見守るだけだった。  
>  と言っても、別に指をくわえてる訳{わけ}じゃない。  
>  むしろ、この距離{きょり}がいいんだと思ってる。  
>  きっと成績{せいせき}も優秀{ゆうしゅう}で、性格もいいんだろう。  
>  彼女の日常{にちじょう}の中に、僕なんかが関わる余地{よち}はどこにもない。  
>  そして僕自身、関わりたいとは思わない。  
>  凄すぎて{すごすぎて}家には飾れない{かざれない}絵画を見ている気持ち、に近いかもしれなかった。  
>  だから、校内で彼女の姿を探そうなんて思わない。  
>  知り合いになりたいなんて、夢{ゆめ}に見たこともない。  
>  同じバスに乗ってくるかどうか。  
>  ただそれだけを気にかけて、会えた時はその偶然を素直に喜ぶ。  
>  それでいい。  
>  いや。  
>  それが、いい。  
>  ……こんな気持ちは多分、そんなに特別なことじゃないんだろう。  
>  憧れて、そして憧れるだけで終わる感情。  
>  おそらく、誰にでもあることなんだろう。  
>  そして、いつかは忘れてしまう思い出なんだろうな、きっと……。  
>

Some attempt at a free translation:

> Rather, I think this distance is good. She's sure to have great grades and a
> good personality. There's no space for me anywhere in her daily life. And I
> myself even don't think that I want to have something to do with her.
>
> It's as if I'm looking at a painting I cannot place in my home as it's too
> wonderful -- or something close to that. Therefore, I'm not going to spend
> my time searching for her at school. I haven't even dreamt of being
> acquaintances with her.
>
> The only worry I have is whether or not she'll ride the same bus with me.
> When I do meet her by chance, I can be glad without reservation.
>
> It's fine like this. No, I mean, this is good. (???)
>
> These feelings are probably nothing special. Feelings of aspiration that are
> nothing more. Perhaps everyone has them. And later, they'll become memories
> that will sometime be forgotten.




With de you're saying "that way/option is fine (too)". With ga you're saying
"that's the way you like/want it, that's your first choice" .

コーヒーにしようと思った。  
I was thinking of ordering a coffee.  
あっ、それがいいね。  
Oh, that's just what I want (too).

紅茶？コーヒー？どっちがいい。  
Tea? Coffee? What do you want?  
紅茶でいい。  
The tea is fine.  
...meaning (something else would pr be better, but if I have to choose)
between those two options, I'll go for the tea.




My suggestion is:

> And that's OK. No, I mean, it's better that way.

As I understand it,「それでいい」 means that something is acceptable, but maybe not
ideal, so I used "OK" instead of "good". 「それがいい」 means that this is the option
that you like or want, so I think it has the feeling of "better than other
options".

I feel that the main point to express is that first, the narrator says
「それ‌​でいい」, but then he notices that this sounds as if he is settling for
something less than ideal. So he corrects himself, to try to sound more
positive about the choice he has made.

However, I'm not confident that I captured the exact nuance of 「それがいい」; it's
just a rough approximation.

It's not really answering the questions, but some other comments about the
translation:

  * "Therefore" and (maybe) "rather" sound a little formal for this context.
  * The translations for 「憧れ」 and 「素直」 may need changing.
  * "I myself even don't think that I want to have something to do with her" makes it sound as if the protagonist doesn't like her.
  * Lastly, at the end, I would use "probably" not "possibly" for 「だろう」. To me "possibly" means maybe only a small chance, while "probably" means a chance of more than 50%. 

