simulated system design interviews at home on an actual whiteboard app with a timer instead of just talking through designs in my head and it broke a bad habit I didn't know I had

Turns out I default to drawing one giant box and talking around it until I run out of time. Doing it under a real clock, alone, with nobody there to nudge me, made that habit impossible to ignore. Now I force myself to write the constraints down before drawing anything at all.