When we do something that we know is not good for ourselves, that is Right Understanding. Yet we go and do it, which is not such a good action. What this basically means is that our Right Understanding and compassion for ourselves are not strong enough. It's as simple as that. But at least our wisdom is saying, "Hey that is not good for you so, don't do that". However we go and do it anyhow.
For those of you who don't know, the battle is with somebody called Mara. Mara is the part of your mind that wants to keep you a slave, in bondage, having more pain, having more Dukkha. Mara is that part of your brain that says, "Let's have a big plate of French fries. And let's have it for breakfast, lunch and dinner." That's Mara. Mara says, "Let's have a smoke!" even though we already know we are coughing enough as it is, our lungs don't feel so good.
I once worked with a guy who was coughing like crazy. I didn't know him before that day, so I just thought that he had a bad cold. "Yeah, I've had it for years," he said. Two weeks later he was dead. He was a chain smoker. He didn't even recognize that he had cancer and he was dead two weeks after I met him. So a lot of people do know that smoking is bad, yet they still do it. They have the Right Understanding, but not enough.
What is actually missing? What is missing is they don't have enough Compassion for themselves. The understanding is already there. We don't have to change the understanding. We have to get more energy behind the understanding, and the energy comes from compassion, "I don't want to cause pain for my body any more. I don't want to smoke. I don't want to waste the money as well. I don't want to lose friends. I don't want to encourage other people to smoke."
One of the techniques that we give to the smokers is to have compassion not only towards themselves, but for the people around them, for 11-year-old boys and girls. What happens to an 11-year-old boy or girl when they see an adult smoking? I was 12 when my cousin tried to get me to smoke a cigarette, because he thought it was cool. And that's exactly it, every time a kid sees adults smoking, the kid sees it as a grown-up activity, something desirable. So with smoking, opening up our Compassion is the essence of how to make our right understanding strong enough that we actually quit smoking.
The essence of stopping the habit of indulging too much, such as eating French fries when you don't need them, is having more compassion for yourself. It can also be balanced by using the food reflection, that's definitely valuable as well. If you're eating French fries with a meal, just having a basic meal, maybe a hamburger and French fries, that's fine. It could be part of a meal. However, eating them after you're done, when you know that you're full, that's what we want to watch out for - the Dukkha that arises from indulging, such as the body becoming uncomfortable and other possible future physical health problems from weight gain, etc. As well as the mental Dukkha of guilt and self hatred. So to have more compassion for ourselves, wishing to avoid this Dukkha, that's the key, to get our Right Understanding strong enough that we then don't do the wrong action.