I use: "What problem does this solve? Can I solve it in a less expensive way (or, better yet, for free)?"
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Brain has a discussion: A short play
Nucleus accumbens: "Ooh, ooh, look! I want that magazine. I love thumbing through 'Interior Design Porn Monthly.'"
Frontal lobe: "What problem does this solve?"
Nucleus accumbens: "Well...um...I'll get ideas for decorating the house. It's important to decorate the house. And I just like it."
Frontal lobe: ...
Nucleus accumbens: "Christ, ok...it solves nothing except temporarily feeding my addiction to glossy magazines."
Frontal lobe: "Um, hmm. Can we solve this issue in a less expensive way? Or, better yet, for free?"
Nucleus accumbens: [Sighs] "Yes, the library has this magazine online. And I could Google design stuff." [Scuffs metaphorical heel on floor] "Aw shucks, Frontal!"
Frontal lobe: "You'll thank me in 10 years. Now let's move away from the Ring Dings."
[exeunt]