I like using the term hang-up to describe another person's unwillingness. It makes for good imagery. Imagine you call up another person to ask them for a favor, and they just hang up on you. In other words, you cannot get through to them because they put their receiver down. Now let us elaborate a little on some of the possible hang-ups mentioned above.
1) Coping Mechanisms - This is a blanket term for any behaviors we develop to help us deal with situations where we feel powerless. Avoidance is a good example.
2) Control Issues - Control issues are often developed as a means of exercising power.
3) Emotional Issues - This is when our emotions such as anger or fear either make us or prevent us from doing something.
4) Immaturity - This is when one has not yet matured and acquired a sense or responsibility.
5) Preoccupation - This is when we are dealing with our own issues and are unaware of what is going on around us.
6) Priorities - This is where people choose to invest their time, energy and effort.
So, when someone is not doing what we feel they should, it is generally due to a combination of the reasons mentioned above. As painful as it may feel or as disrespectful as it may appear, it is their own personal hang-up and has nothing to do with us. We also have our own personal hang-ups, and rather than focus on breaking down other people's hang-ups, we should be working through ours. And interestingly, when we take the focus off of having our needs met by someone else, other people soon become very willing.