Smoking
can cause several bad effects,
such as bad personality and diseases,
smell of cigarettes which are not pleasant to anybody at a especially to non-smokers.
The smells stay with your breaths and your clothes all day all night
. So, people always avoid you.
This you don't have a good personality to approach people.
Besides the bad personality, smoking can also destroy your lungs and finally cause some irritation in your lungs and brings in diseases, like a lung cancer.
Furthermore, people who don't want smoke can also get the disease if s/he breaths in the smoke.