"They are who they are, not who I want them to be."
And it's not my responsibility to change them to meet my desires. If they were who I want them to be, they may end up getting into more trouble than they are in now. In other words, I must accept that I don't know what's best for everyone else. I must let people be themselves. I must learn that everyone is a human, so everyone has their own issues. This should not be a cause of resentment for me, but cause for appreciation, sometimes gratitude and sometimes empathy. Just because someone is different, and has different goals, does not mean that I need to fix or change them. Letting go of others is a way to reduce my own stress and actually makes me happier. Just because they are different, does not mean that they are wrong.
Letting go of control of others makes you less resentful and more serene. So, today, enjoy the differences. If someone is making you miserable or craving a drug, you may need to remove yourself from the situation and create healthy boundaries, but more often than not, you don't really need to do anything but let the person be.