I work in the medical field, which requires me to view large xml files and multi patient csv files with years of patient history. The CSVs contain embedded pdf strings that are long strings of bytes in the file. Emacs struggles to copy and paste, and move around in the large CSVs.

For the large XML files, I have to switch to fundamental mode, because it struggles to highlight everything, and sometimes the xmls are pure ass and are basically all on one line. I've written a python script that will prettify the xml because emacs locks up when I try to do that. My colleagues just tell me to use sublime text.