Alan Kay on programming languages as user interfaces: "Even if you’re designing for professional programmers, in the end your programming language is basically a user-interface design. You will get much better results regardless of what you’re trying to do if you think of it as a user-interface design."
Steve Yegge on the relative difficulty of high-level and low-level programming: "Observation: systems programmers look down on application programmers. Pop culture is that systems programming (kernels, drivers, real-time OSes, etc.) is harder, possibly since they're equating app programming with just laying out the UI. I've done both — or all three, counting doing a bunch of tedious UI layouts in various frameworks. App-level programming is harder than systems programming."
m4 manual page on Turing tar pit addictiveness: "Some people found m4 to be fairly
addictive. They first use m4 for simple problems, then take bigger and bigger challenges, learning how to write
complex m4 sets of macros along the way. Once really addicted, users pursue writing of sophisticated
m4 applications even to solve simple problems, devoting more time debugging their m4 scripts than
doing real work. Beware that m4 may be dangerous for the health of compulsive programmers."