How to think like both a designer and engineer

The shorthand I use: an engineer asks can we build this, a designer asks should we build this. Neither question is enough on its own, and the people I learn the most from hold both at once.

In practice, that means catching yourself mid-thought. If you're sketching a flow and feel productive, the engineer in you should be quietly asking how this fails — what happens on slow networks, what the empty state looks like, who clicks the wrong button first. If you're deep in implementation and feel productive, the designer in you should be asking whether the thing you're building is the thing anyone actually needs.

The trap on both sides is the same: confusing momentum for progress. A beautiful mock of a feature nobody wants. A clean refactor of a system that should've been deleted. The seam between the two roles is exactly where you notice that, before you've spent a week on it.