At one company where I worked, I resented the fact that the executive assistant to the CEO made more than I; after all, she was non-technical and "simply a secretary". Then she had a heart attack at her desk and died instantly. I felt guilty for my thoughts and resolved to find out exactly what her job entailed.
About 2 years later, her replacement was struck by an aneurysm at her desk and died several weeks later. I had been interacting her a lot for work-related projects and had had learned how stressful, difficult and important that job was and did not begrudge her her salary at all.