You can not know what you're doing and use it to write slop.

Or you can set up your project with best practices in every way with full design documents and code that flows from design and full rigor around everything.

I do it the second way. And so yes, I find myself being confronted with so many edge cases that I just never thought about before. And I'd say it about doubles the time it takes me to deliver stuff, and I'm not always sure it's worth it.