Man is not a soulless machine. He often experiences fatigue, fear, irritation. All of these (and many more) factors make him nervous. This is quite understandable and natural. However, you shouldn't be nervous. Why?
There are situations when this is simply very harmful. A classic example: when a pregnant woman is nervous, she thereby does a "disservice" not only to herself, but also to her unborn child. After all, the fetus is very sensitive to any changes in the hormonal background in the mother's body.
If a person with heart problems is nervous, it can simply end up with a serious complication, up to a heart attack. Etc. There are a lot of examples from the field of medicine.
But suppose we are talking about a perfectly healthy man. Can he get nervous? Again, not worth it. For example, a person is engaged in responsible work that requires maximum precision and concentration. And he was very nervous - either because of problems with his superiors, or because of purely family troubles, or maybe for some other reason. What are the consequences? The person is upset; accordingly, his reaction and attentiveness have worsened. The risk of error (incorrect calculation, incorrect assessment of the situation, incorrect decision-making), accordingly, increases many times. And the cost of that mistake can be prohibitive.
Well, what about the purely everyday side of life? Already in the family, among the closest people, can you relax, give free rein to emotions? And it's not worth it.
The fact is that a nervous person sometimes imperceptibly “electrifies” everyone around him. This can be compared to some particularly contagious infection: one member of the family caught the flu virus - soon the whole family fell ill. A nervous mother begins to "shake" the children: why the lessons were not done on time, why the room was not cleaned. Moreover, in an irritated, offensive tone that she does not even notice. Children (especially if they are in adolescence) may snap back: they say, they are already tired of your nit-picking! A loving grandmother hastens to intervene in the flaring up conflict: do not bother granddaughters, they will grow up - they will work out more! And off we go. As a result, spoiled mood and deteriorated health. And it can even reach an ambulance call.
So try not to get nervous anyway. Master the technique of self-hypnosis, learn to control yourself. For your own good.