It's hard to love people deeply and genuinely because to do that, you have to love them as they are without any hope that they will change. If you can't love someone as they are, right now, at this moment, you will never love him/her. The mistake that's made all the time by Christians, with all the best intentions, is loving pre-Christians for who we hope they will become, post conversion, rather than who they actually are right now, at this moment. Unfortunately, this is anything but love, and the other person, particularly postmodern pre-Christians almost always experience it as a bait and switch. The end (conversion) is worthy, but the means by which it is achieved can easily end up hurting the object of our well-meaning affection far more than never knowing us could have, and who will they blame? Us? Not usually. Typically they blame God, directly or indirectly.
That doesn't mean that we condone poor behavior. I teach at a local Mission, and I see poor behavior all the time. It breaks my heart when one of the resident students goes out and lets loaded or something. I hate it, and it never gets easier, no matter who it is. Sometimes they come back though, or I run into them on the streets, so I get a chance to love them a little. I resist the urge to scold the behavior. Instead, we talk about why it happened. I'm far more interested in that. The addiction is just a symptom of the real problem..this is true for lots of behavioral stuff. The thing is, in almost every case, this person already knows that he's screwed up. His sense of failure and shame is very, very deep. I can love him deeply and genuinely if I can love him at that moment, not trying to change him, but at the same time understanding that God is at work. If I can understand that, then I'm free to love anyone at any time, at any point in their journey to Christ.
This will take some practice. Be quiet, inside and out. Try to connect with how much, how deeply God loves this person, exactly as he/she is right now, at this moment. Step into the cage. This is your chance to love someone without any hope that you'll get anything in return. This is love. This is mercy. This is Jesus.