I went through my copy of the EoTVGS 2nd edition and wrote down every show I'd actually seen and had an opinion about, which got me a list of about 70 shows. Then I tried to remember shows I like(d) that postdate the publication of that EoTVGS edition and added those. Then I started crossing off shows until I got to 50. Then, well, I put those 50 in some semblance of order and e-mailed the list to Matt.
And almost immediately, I realized I had forgotten a recent show and had to wedge it in somewhere and eliminate a show from the bottom of the list and resend to Matt (I know, there wasn't a strict 50-show limit, but sometimes I'm too conscientious for my own good).