"Extremist Programming": try to apply a technique everywhere, not just where it's commonly used.
Related Posts
GIMP is huge tool that I certainly haven't mastered, but it's so useful to have around.
I used it this week to convert images from obscure formats to common ones. It's a great swiss army knife and runs everywhere.
TIL Tcl has a notion of 'safe interpreters', a mode where you can run untrusted code in a sandbox: https://www.tcl.tk/man/tcl8.4/TclCmd/safe.htm
Not many programming languages have this, but it's way safer to include in the implementation than try to build as a userland library.
What are the most popular languages that have used an AST walker for their implementation?
I know Ruby used to do this, but there must be others.
(I'm interested in the lowest PL speed that users will tolerate if you have awesome features.)