At the age of 45 I decided to learn the English language. Not that I didn't know the language, but to improve my command over the language, I joined English academic classes close to my house. In one class, the instructor gave us a sheet of a hundred words and told us to write the opposite of each word as homework. At home I sat with that page but though I could manage the easy words quickly, for certain words I had to take the help of the dictionary. Feeling relaxed and like an achiever, my new found enthusiasm forced me to explore some more words. Exploring the dictionary, for every word I found the opposite word (except all forms of nouns). The entire night went on exploring words, but the night was not enough to complete the dictionary. I had enough time to hand in my homework, so the next day, after work once again I sat in through the night and started exploring opposite words from the dictionary.   The exercise was easy, but suddenly something struck my mind. Instead of finding the words which have opposite words, I should look for words that do NOT have any opposite word. After going through sleepless nights that week, I could not find a single word which doesn't have an opposite word. This amazed me and forced me to conclude that without the opposite word the original word doesn't have its real meaning or value. In other words, every word is incomplete without its opposite. The conclusion forced me to think differently. Although many questions remained unanswered in my mind, the one thing I concluded was that these words are created by humans and every human possesses two qualities within himself, Positive and Negative. Similarly he created words with opposites. This proves that whatever we welcome in our life, we will also be welcoming the opposite of it. And at the end of the day we will complain about the negative forces surrounding us, making us weak, dull, pessimistic  and so on...Isn't this strange? Which of the following idioms may the author agree more with?
Every coin has two sides. Easier said than done. All roads lead to Rome. Kill two birds with one stone