What kind of calligraphy lines are good lines?

In fact, judging from calligraphy, a person's character is one-sided, especially from lines. Hard pen calligraphy is not the same as brush calligraphy. Some people write well in brush calligraphy, but not so well in hard pen calligraphy, which is also very common. As for calligraphy lines, we can see a person's character from the following points: urgency, severity, cleanliness, font and so on.