this is what I have to say, you're going to have to make what sense of it you can...
say you've been given a temporary postition at a good company, you like your job, the boss seems to like you most of the time, you do a good job and there is often promise of you being given a full time postition with the company.
Just when you think you will be given permenant status your boss interviews another cantidate, however she doesn't hire that person or relieve you of your position. You continue on with your temporary status occassionally being offered the benifits of a full time employee yet your boss continues to interview this other cantidate never giving them the job.
How long are you going to work for this company? How long are you going to enjoy the work you do? how long are you going to stay commited to this company with the constant promise of a perminant position that year after year doesn't seem to come? When will your boss appreciate that they cannot keep expecting you to work under the pressure of constant threat of loosing your job to this other cantidate they keep interviewing but never hiring to replace you? When will you finally give your two week notice? Will you not give your two week notice but keep working, eventually becoming drained and tired and less productive as a result of your underappreciated status with the company.