In the old days of web design, we had to put all of our files in folders, so having a path like example.com/category/sweaters/cashmere/winter-special.html was really common. You could also remove any part of the path and be sure you would get an index page, such as example.com/category/sweaters/index.html.
Have you ever had a client call you up saying their new website, which has not launched yet, is showing up in Google?
No matter how much you think, "we won't get crawled", those pesky search engines always seem to find your development site. Thankfully there is an agreed-upon standard for removing a website (or just certain pages) from search engines called the robots.txt file.
Working on an old Drupal 5 site (I was upgrading core), I came across a very odd bug. Every time I submitted a form, I was being redirected to the frontpage of the site. I had recently installed Path Auto and Global Redirect, so I thought one of those could be causing the problem.
With Global Redirect on, when I tried to visit a normal URL with an alias, in this case, node/2 that was aliased to services, I was also getting redirected to the home page.