Why the more grown up the world is more gentle?

To see a word, that is: you are more and more indifferent to this world, you think you have grown up. In fact, not true growth is more and more gentle on this world. I just did not understand this sentence just because of adult ritual because I was becoming more and more indifferent ... So I wanted to know the meaning of this sentence and I also wanted to correct myself.
Once called takeaway, when delivered, the soup spilled in half. Takeaway brother sorry to say: "You see, this soup, do not know what is going on, I was very careful, it spilled out." I took the soup, have not had time to speak. He rubbed the rub corner, hesitated for a moment, said: "Otherwise ... I ... lose money to you." I immediately said: "No, there are still half a bowl, but also drink." Thought , I added: "You're careful next time." Thank you brother, turned away. I'm afraid he still worried about his heart, and opened the app to give him a special five-star praise. However, just a few years ago, I was totally different. I would think some people how stupid, why some people can not do their own simple things, some things that is clearly who is who is wrong.
I am impatient and irritable. Now I do not think I was wrong at that time, but I feel very mean at that time. Because I started to understand others. Not a thing, but his reason for doing this, his life experience, his limitations and helplessness. Then I learn to respect others. From his point of view to think about everything. I learn sympathy, tolerance and understanding. Is there any reason why I should not forgive that a young man who works hard on his own hands, who is willing to take responsibility and may not have too many choices for his life? A bowl of soup, for me, is just a condiment for eating. A careless, lose out may be his life-long day, or even his dignity, his confidence in life. And an understanding, a casually care, may make him a happy day. When I have this ability to understand others. I am willing to treat this world gently.

看到一句话，说的是：你对这个世界越来越冷漠，你以为你成长了。其实不是，真正的成长是对这个世界越来越温柔。才刚过成人礼的我不太理解这句话，因为我正在越来越冷漠…所以想知道这句话所指的含义，也想改正自己。
有一次叫外卖，送来的时候，汤洒了一半。外卖小哥不好意思的说：“你看，这个汤，不知道是怎么回事，我很小心了，它还是洒出来了。” 我接过汤，还没来得及说话。他搓了搓衣角，犹豫了片刻，说：“要不。。。我。。赔钱给你吧。” 我立刻说：“不用了，这还有大半碗，还能喝。” 想了想，我又补了一句：“你下次小心一点。” 小哥说了感谢，转身走了。我怕他心里还是有担心，又打开app特地给他补了一个五星好评。 然而就在几年前，我却是完全不同的样子。
我会觉得有些人怎么就那么笨，为什么有些人不能把自己简单的份内之事做好，有的事明明就是那个谁谁谁错了。我缺乏耐心，容易急躁。 现在的我不觉得那时的我错了，却会觉得那时的自己很刻薄。 因为我开始理解别人。不是对一事一物，而是他做这件事的原因，他的身世，他的局限和无奈。 然后我学会尊重别人。从他的角度出发去思考每件事情。 我学会同情、宽容和谅解。
我有什么理由不去谅解一个靠自己的双手努力工作、分得清是非愿意承担责任，又可能对生活没有太多选择的年轻人呢？一碗汤，对我来说只是吃饭时的佐料。一个不小心，赔出去的可能是他一天的营生，甚至是他的尊严，他对生活的信心。而一个谅解，一句随口的关心，可能会让他这一天都很愉快。 当我有了这种理解别人的能力。我愿意温柔的对待这个世界。