The great thing about green screens is that they are so easy and so quick to use. Basically, a screen appears, you enter some information, press tab, enter some more information, and press enter. It’s quick, it’s simple to use, what’s not to like? And that’s how so many mainframers feel. They’ve been using green screens since they were really green to get their work done accurately and efficiently. ISPF, SDSF, and SMP/E are just so straightforward to use with a 3270 display.