Giving credit where credit is due....

I would be pretty pissed off if someone took credit for something i put my heart and soul into. Most of the time, people take credit for small things, like if they want to make someone like them, they may take credit for something ot impress them, but taking credit for something big like a cure for cancer , or a pulitzer prize paper, is just awful.I dont understand how someone can feel they have the right to use someone elses work. How can they , in there right mind, look themselves in the mirror knowing what they did to someone else? They could have ruined there life's work or taken there livelihood. I am glad there are rules against such things, i really am.