I'm not sure how could you write anything if you don't think about the problem before? I didn't like my last whiteboard interview because I just stare at the sc

I'm not sure how could you write anything if you don't think about the problem before? I didn't like my last whiteboard interview because I just stare at the screen for a long time before writing anything, and sometimes even the best design decisions happen outside when I'm walking or under the shower.