Sri Sri Ravi Shankar:
You know it is bad and you still do it. Why do you do it, are you asking me? That is ok. You should wish that circumstances would change and know that opposite values are complementary. That gives you the strength. And, know that things change.
There are only two reasons why you don’t follow knowledge or wisdom:
First: Bad habits. Old habits don’t leave you so fast.
Second: Your temptation of doing wrong gives some pleasure. For example, you know that eating too much of ice cream would increase your sugar level as your doctor has warned you, but your temptation says, 'No, I should eat that. Just one more day let me eat it.' You do it because it gives you pleasure.
It is ok, you can violate the laws as long as you are ready to take the consequences. Eating after 8 pm is not good, you know? But if you still do, then keep awake in the night, keep burping and keep suffering with indigestion! If it is ok with you, then do it.
So, only these two things stop you from following the knowledge.
Like, you know that smoking is bad for health but you still smoke. Smoking is not giving you any great pleasure but to drop it has become so difficult because it has got ingrained as a bad habit in you.
Now, habits can be overcome only through three things:One is out of greed. Say, someone tells you that you will get one million dollars if you don’t smoke for one whole month then you will say, 'Why one month, I will not smoke for 35 days. Five extra days to make sure the counting is right.' Greed can stop you from habits that you don’t like.
The other is fear. If someone says you will get these different types of cancer if you smoke, then you won’t touch it.
Third is the promise to a loved one. If you made a promise to a loved one then also you won’t do it. The love for them will will stop you from smoking.
So, I prefer the last one to the other two.
Or, in the end you will realize by yourself, 'Oh! It is painful. It is misery that I am buying by continuing with this habit.' So, one day when you realize this, then it will drop the habit itself.