Ant writes "This Nature.com news article reports that potential readers can make snap decisions in just 50 milliseconds: 'Like the look of our website? Whatever the answer, the chances are you made your mind up within the first twentieth of a second. A study by researchers in Canada has shown that the snap decisions Internet users make about the quality of a web page have a lasting impact on their opinions...'"
I've never been canoeing before, but I imagine there must be just a few
simple heuristics you have to remember...
Yes, don't fall out, and don't hit rocks.