The website test
I love looking at creative marketing websites. Apple's iPad OS page is a joy to scroll through - the colors, fonts, and animations work in perfect concert. Tesla's design-your-car experience feels like a game. Github's interactive globe lets you spin it around and has pins that represent recent PRs. All three of these companies made their website a joy to use. After all, how could they not? A website is every company's most important public representation. While a store might attract thousands of visitors per months, big company websites attract tens of millions.
And yet I frequently come across large companies with websites that are terrible. A great marketing website alone is not a reason to invest in a company, but to me a bad one is a reason to pass. It's a canary in the coal mine – a guarantee that a company doesn't understand how to prioritize things and, in all likelihood, means that other parts of the company are also incompetently run.