It means it's easy to control my pen, so I can stop writing.
Love or sadness in my heart can't be controlled, and it will naturally be revealed inadvertently.
The second sentence: In the long life, why does the joy of falling in love at first sight always fade, but the most urgent thing is the most beautiful time?
It means that in our long life, happy time is always rare, but it is also the fastest. We miss them, we cherish them, we sigh that we never cherish them when we have them, but we miss them even more when we lose them. This sentence is similar to "Time easily throws people away, cherries are red and bananas are green".