Most non-lawyers think lawyers are unprincipled, not to say unethical. This part of society tends to believe that lawyers have no ethical standards, when in fact, ethics are an important part of being a lawyer. It's not that lawyers are unethical. If they are, they don't last very long. But they have to be clever, they have to think on their feet, they have to retain minute details of the intricate fabric that makes up the American legal system - a system that, because it is both federal and state, is unlike those that govern most nations of the world.
Lawyers are necessary.
And I have to think that most lawyers are not really worthy of being the butt of jokes, even if they've become resigned to hearing them. I have to say that because some of my best friends are lawyers. After talking to them, I've come to realize that lawyers are unloved not because they are unprincipled, but because their basic function is to act as advocates. The lawyer's responsibility is to uphold the law, but an equal burden is to do the best he or she can to defend a client or to get him or her the best possible result of any legal action. This doesn't mean one's counsel breaks the law, they just try to use it to their client's best advantage.