Compassion to friends: stepping in vs. letting them learn on their own There is a story about how the Buddha will knock on your door if your house is on fire, but he will not kick it down because you have to answer the door yourself. This is analogous to the Four Noble Truths, in which one must realize their suffering, and from that they can make the effort to find the path to the cessation of suffering. The Buddha will not force you down that path, nor will he be your savior; he will only help you if you ask him. However, the Buddha also asks those to practice sincere compassion for others.

My question is: if I see a friend suffering (let's say from a slight alcohol abuse or they think that they are ugly), yet I think they will never understand their suffering, how can I give my compassion to that being that needs help to deal with their suffering, when their understanding of suffering must come from within? They need to come to the realization of their suffering, but I know that these people will never see the light themselves. Where's the balance in this tricky situation? These friends are unwilling to change their unhealthy habits, but I, as one who tries hard to practice compassion, find it hard to just let it slide and hope someday they will realize their suffering and understand that it exists, and that there's a path to the cessation of it.

Any insight would be much appreciated. And I hope my thoughts make sense to some of you.
The truth about the Buddha, as far as I can see, was that he was disinclined to do much of anything after his enlightenment:


  'With great pains have I acquired it. Enough! why should I now proclaim it? 
  This doctrine will not be easy to understand to beings that are lost in lust and hatred.
  'Given to lust, surrounded with thick darkness, they will not see what is repugnant (to their minds), 
  abstruse, profound, difficult to perceive, and subtle.'
  
  -- Mv. 1.5 (Rhys-Davids, trans)


Of course, we see a complete reversal of intention after the Buddha was first asked to teach and he looked and saw "beings whose mental eyes were darkened by scarcely any dust, and beings whose eyes were covered by much dust, beings sharp of sense and blunt of sense, of good disposition and of bad disposition, easy to instruct and difficult to instruct, some of them seeing the dangers of future life and of sin." (Ibid)


  'Wide opened is the door of the Immortal to all who have ears to hear; 
  let them send forth faith to meet it. 
  The Dhamma sweet and good I spake not, Brahmâ, 
  despairing of the weary task, to men.'
  
  -- Ibid


But the point remains that his whole life of teaching depended upon being asked to teach. The first question you have to ask yourself is, "why help someone else at all?"

Some of the things you have to keep in mind when answering are:


Will I actually be able to help this person, given I'm not a fully enlightened Buddha?
Will they accept my help or will they reject it?
Will helping this person distract me from my own practice or will it help make me a better person?


What you shouldn't do is let your partiality for this person lead you to spend more energy on them than is appropriate; if the same amount of energy could obtain greater results elsewhere, it stands to reason that you work for the greatest gain possible.

Compassion means an attitude of non-harming; it fails when it becomes a desire to free others from suffering, because that is a type of craving that leads to suffering when it is unable to obtain its desire. This means that true compassion requires the person to approach you in some way - approaching them to probe into their personal life or nagging them about seeking help is not compassion. 


  Compassion  is characterized as promoting the aspect of allaying suffering.
  Its function resides in not bearing others’ suffering. It is manifested as non-cruelty. Its proximate cause is to see helplessness in those overwhelmed by
  suffering. It succeeds when it makes cruelty subside and it fails when it produces
  sorrow.
  
  -- Vism IX.94 (Nyanamoli, trans)


Of course, simply crying in your presence or making a fool of themselves would be enough to elicit an appropriate response, since it would be cruelty to repress the intention to comfort others or warn them of their bad behaviour, etc. 

In most cases, your friendship with the person will put you in a position to nudge them in the right direction as a simple matter of course. What you don't want to do is want to help them, since that will have negative consequences, most likely for the both of you. In the end, we are all responsible for our own fate; this is what sets Buddhism apart from theistic religions, that we have to save ourselves.


  Let one not neglect one's own welfare for the sake of another, however great. 
  Clearly understanding one's own welfare, let one be intent upon the good.
  
  -- Dhp. 166 (Buddharakkhita, trans)


Still, you should not underestimate your influence on others, nor should you dismiss the power of small acts of goodness.


  Think not lightly of good, saying, "It will not come to me." Drop by drop is the water pot filled. Likewise, the wise man, gathering it little by little, fills himself with good.
  
  -- Dhp. 122 (Buddharakkhita, trans)


Simply being mindful and conscientious around other people can have a profound impact on them over the long term, if you are patient and truly compassionate with them.