If you work in software development, you've probably heard the phrase "Code like the user was dumb". Its intention is to avoid making your app too complex, and also most users will indeed act like they were dumb.
But there is another type of users: the smart ones. The people who try to push out of the boundaries. In our digital world, these people are called hackers.
As a quick note, a hacker is not a delinquent. Wikipedia defines Hacker as "any skilled computer expert that uses their technical knowledge to overcome a problem". I tend to use Wikipedia for democratic definitions because as anyone can edit, there's usually a discussion and a consensus reached for these things.
These users will use your product too, and will probably try to jump above any limitations you've created. And you (usually) don't want them doing that. That's why you have to take all this into account when building your product. Unfortunately, as makers rushing to ship great things, we often forget to do it.
Some time ago, I published the shortest 200wad ever, with only 40 words. I did this, not only because it's cool, but just as an example of this (and as a way to keep improving this site).
So here's the first (and the last) 200wad with an image: