Poking a bruise

I work a heart-wrenching job. I watch people lose loved ones to disease, dementia, and depression. I watch people lose everything: freedom, ability, communication, comprehension. It is my job to make the suckiest situations suck a little less. I leave my work week physically and emotionally exhausted. So what is it that makes me, at the end of this work week, choose to write a research paper on Dementia, only to discover, once again, just how hopeless this disease is?