Insurance Adjusters may defend or claim that your case has little value for several reasons.   Many of these excuses for not paying and lowering the value of your case may include:

1. How the injury is predated or non-related. Often the insurance company will claim that the injury already existed and that they shouldn't have to pay,  This excuse just isn't valid.  The insurance company takes their victims as they find them the fact that a person is already sick or aged does not mean that the insurance company is not liable. 
2. Non-related Injury.  Often the insurance company will claim that the injury was not their fault but instead that it is the fault of someone else or something else. It is their responsibility to prove that it was due to someone or something else not yours to prove that it wasn't.  Along with this they often claim that the accident only aggravated a prior condition this is not an excuse for not paying. 
3. Victim Credibility when insurance companies use every trick in the book sometimes the victim feels that it is ok to exaggerate his claims.  This is a bad mistake.  Fraud will hurt your case far more than exaggeration and lying will help.  Juries, Judges and insurance companies are experts in uncovering false claims.  Insurance companies love to lower damages and to make cases worthless by showing fraud.  It is better to have poor facts than fraud on your part. 
4. Severity missed work, and property damages help to prove that you were severely injured.  The lack of it tends to prove it wasn't severe. 
5. Attorney Experience and Reputation  Attorneys have certain reputations.  Some large PI firms may have the reputation for settling quickly other firms may have a reputation for going to trial and others will have a reputation for dropping the ball on a case.  Your attorneys reputation will have a small factor in the outcome of a small case.  Small cases are settled in the stream of other cases.  Attorney Reputation is a large factor in the settlement of major cases if the insurance company doubts that he can take it to competent trial. 
6. Doctor Reputation  Your doctors reputation will effect the outcome of your case.  If you have a neuro-surgeon testifying for you it is better than a chiropractor testifying against their expert.  However if you have a paid for "expert" it may lower the value of your case. 
7. Mitigation of Damages The insurance company may claim that you increased your damages by refusing medical treatment or otherwise failed to keep damages to a minimum.  In workers comp cases the worker is required to cooperate with medical treatment or his monthly check may be cut in half until he does cooperate. 
8. Your ability to Hold out for Settlement  Getting the Maximum for your claim sometimes means being able to hold out for more.  The insurance company is always happy to pay less today if you will settle today if the insurance company sees that you cant hold out it will offer even less. If you fail to treat your case as important or if you are impatient the insurance company will view the case as weak. 
9. Attorney Client Problems Sometimes clients become problem clients and the attorney just isn't able to work with them.  It is very important that you get a quality attorney up front and that you not switch attorneys several times. When this happens it creates the impression to the judge and the insurance company that you are a problem client that probably has a poor case and that the case has little value.