Some situations in our lives can bring out characteristics that are normally suppressed. She was very patient and polite all over the story. Even under pressure she functioned so well, until the point that Mr. Van Daan stole the food, and her reactions changed. We discover in her feelings that we, the readers , didn't know before. This situation teaches us that if a man is very calm in his character, it doesn't mean that under pressure he will always behave in a calm way.
Pressure can change a person totally.
There are cases that change people for the good and cases in which people change for the bad. There are people that in situations of starvation they will become bitter and angry or sad all day long. This kind of people lose their hope and think about the worst. They are pessimistic. The opposite are people who stay calm ,happy, they will encourage others .