When you do your preflight, you need to be really careful about making an "error of expectancy" It's when you do the same thing over and over and never find anything wrong. You've never had a problem before, so your preflight becomes just another ritual. There might be something clearly amiss and you just might not notice it.

Top dogs need to be extra careful!

You owe me a banana for each F that you missed. There are 6 of them, by the way...