Droopy (or Droo.py) is the most idiot-proof way for other people to get files to your computer that I have found, and I have been using it for a year now.
It’s a Python script (so you would need to have Python installed) that creates an HTML page that lives on your computer. You give your IP address to whoever wants to send you a file, and they go to the page and click “send file,” which gives them a way to send you a file directly to your computer (rather than via a remote server).
It’s definitely not idiot-proof to set up (if you want people to be able to reach the site from the outside world, you have to set up port-forwarding on your router), but the important thing, and the thing that makes it my go-to way for somebody to send me a file, is that I need to know nothing about their computer, and neither do they. Once I get it set up, it is virtually impossible for the other person to mess up the file transfer.