hbb, it seems to me, and I'm no shrink, that people with low self-esteems may find it difficult to be with someone in a better place. Perhaps they feel threatened, perhaps they feel worse about themselves, or maybe they think it won't last whenever the other person realizes who they are with. There could be a multitude of reasons why they don't feel comfortable being with someone who is successful, not an addict, etc.
I've been to dinner with professionals at 5-star restaurants, with expensive wine and food, and conversation with people who have millions. The people there who do that all the time probably feel comfortable in that setting. Me? I'm really more comfortable having dinner at a regular place with some close friends, some fried mushrooms and lots of laughing without fear of watching what I say.
Perhaps the analogy is similar.