I've never had a good product idea while sitting at my desk, staring at the screen, trying to have one. They show up in the dumbest places in the shower, on the toilet, or at 3am when I've decided sleeping is the priority.
Mine came while I was arguing with an AI writing tool at 2am. It kept giving me citations that looked perfect and pointed to papers that were never published. I closed the laptop, went to bed, and couldn't sleep because I kept thinking "someone should just make it cite only what I actually gave it."