I agree with Xeney's comments. To be a good lawyer, you have to be able to communciate, sometimes forcefully, and think well on your feet. You can't be easily intimidated, but you also have to intuitively know when to shut the heck up or eat humble pie. You have to be patient and pay attention to the details but wise enough to keep the big picture in mind. Unfortunatley, there are a lot of stupid attorneys out there, so it helps to be smart, meaning that you think in a logical, linear fashion and that you are committed to knowing the area of law in which you practice. I think it helps if love to learn, because the learning never stops (or at least it shouldn't).

But smart isn't everything. You also have to have people skills. The most successful lawyers I know have figured out how to be strong adversaries for their clients without making enemies in the process. Generally speaking, that means that you play fair, are firm but courteous, that you don't fight just to fight, and that you practice with integrity.

I think to be a happy lawyer, you have to strike the right balance between work and the other things in your life. Find a job that plays to your strengths and is consistent with what you want out of your life and career, while accepting that no one job is perfect. Try to take the work, but not yourself, too seriously.