Last summer, a buddy and I just launched on a small lake, right around dawn. The short channel to the lake had some fog, but nothing too bad. When we got to the main lake, different story. The fog was so thick we couldn't see a foot in front of us. We were literally in a cloud. We were so worried about not hitting the left shore, we almost hit the right. This lake has a somewhat unforgiving shore, but luckily we saw it at the LAST moment. To be honest, it was pretty scary.
Once the fog cleared up we had a good laugh.