English is direct or Lanugage is difficult

These days, I've been working on writing practices for the coming CUNY ACT writing test. It tests if students have adequate skills to think and write logically. Unlike abstract writings like poems, it has to have concrete and specific ideas to show that I am able to think critically and write logically. But, frequently, I use broad ideas. Whenever my professor evaluates my writing, she says, "your ideas are too general". Also, a friend of mine pointed out that I often use general "words" in writings, such as it, do, does, etc,. I was thinking how I can change this writing habits.

And then, a hint to understand the meaning of using a "specific" word came up to my mind during conversations with my roommate this morning! My roommate was taking a spoon of salt from the kitchen to the bathroom! She told me that she has rhinitis. That's why, every morning, she uses salt and water to rinse her nose so that she can breathe easily, instead of taking medicine. I replied to her, "that's good because you don't have to rely on a medicine".
After saying that, I realized that it was not clear what good meant.

"Good" is a simple and useful word. It can be used for every occasions. You could use it as "ok", "tasty", whatever. In my mind, I was thinking it would be healthy because she doesn't use any chemical medicine but natural salt. This thought was a big realization, like "this is the difference!!". I was lacking of sufficient words that express direct meaning, for this situation, "healthy". It's simple and nothing is difficult, but I had had a bad habit to use easy and useful words. This is a huge realization for me to understand my weakness.

Actually, I thought this weakness cane from the difference between English and Japanese because various meanings are included in Japanese words. Like, "いい" for "オッケー" or "おいしい". Mmm, wait a minute, it is the same thing! Well, my guess is Japanese language includes more broad and general words as much as English has. In Japanese conversations, we are usually guessing what the other says because our language doesn't have to have a subject all the time. In contrast, English has to have it. It is much more direct. Most important thing is to understand that no one can read your mind!!, so I need to use exact words to express my thoughts choosing the right words, no matter what cultural or language differences there are.