I am pretty sure that nothing I've done is harder than being poor.
I've done quite a few things that people would say are hard, and that might have impressed people. I was an Eagle Scout (no, stay with me, that's impressive in some circles). I applied to and got into a number of colleges. I took courses that included science labs. I passed a lot of midterms and finals. I got into graduate school. I passed my qualifying exams, and wrote a thesis. I wrote papers and successful funding proposals. I gave lectures. I won a couple awards. I moved to pursue opportunities. I figured out how undocumented software, which some engineers wrote, worked by reading thousands of lines of source code. Along the way, I changed a bunch of diapers, cooked dinners, cleaned house, and helped comfort teething children.
The thing is, I'm privileged in many ways. My family, friends, and even society prepared me for every challenge that I have faced. Moreover, when I failed at something (for instance, I'm a pretty poor athlete), they helped me find a new path on which I could succeed. I'm also lucky, which is a form of privilege. My talents lie in math and physics. So, society is willing to pay good money for me to learn and work in fields that use them. I don't seem to have inherited any addictive genes; I've never had to struggle with quitting anything.
I have never been poor, so I have to imagine what it would be like. Learning to read and to do math is tough for many. I can't really imagine what it would be like if my parents and friends also struggled with learning those things; if my parents couldn't afford tutors; if my schools lacked resources to give me personal attention to help me to learn; if I was hungry while trying to learn; or if society looked at the statistics for my neighborhood and expected that I should fail.
I did some moderately stupid things as a kid, mostly involving non-permanent insults to other peoples' property. I didn't get caught, so there were no consequences. I can't imagine what it would be like if society had been waiting to pounce on me if I failed. We have policies, like Stop and Frisk in New York, that are designed to pounce on the poor. Society has run the numbers, and realized that poor people are more likely to be involved in crime. So, the police constantly check up on young people, who everybody knows are wired to make mistakes, in order to catch them and incarcerate them when they make mistakes. I don't doubt that doing so will prevent some crimes. But, I can't imagine how many opportunities would have been cut off from me if I was caught making a mistake while being poor.
I can't imagine the stress of being a parent while being poor. Parenting is enough work, with all the lack of sleep, the things to clean up, the worry about illnesses and injuries (real and potential), and the lack of personal time. What is it like to add to that, not being able to afford food, or day care, or heat, or a roof over our heads. That is real stress. That is truly hard.
I'm sure I've only scratched the surface. But even with my limited ability to empathize, I can say with fair certainty, Being poor is harder than anything I've ever done.