I second EP194: Exhalation as best ep ever (Ted Chaing is an amazing writer!)
Impossible Dreams by Tim Pratt is an absolute necessity, because I know how much love it gets around here. And, well, Tim Pratt needs representation.
EP433: That Other Sea by William Ledbetter. Great alien perspective episode.
EP339: “Run,” Bakri Says by Ferrett Steinmetz. Total classic, with the only downside being that Edge of Tomorrow covered a lot of that ground in film version a few years after it "Run" came out
You need a silly / irreverent episode. I nominate either
EP380 Punk Voyager by Shaenon Garrity or EP169: How I Mounted Goldie, Saved My Partner Lori, and Sniffed Out The People’s Justice by Jonathon Sullivan.
EP116: Ej-Es by Nancy Kress is also a wonderful suggestion