Taken from a Medium post:
Programmers have to worry about things no sane human being ever considers. You drop a “last name” field in your design without thinking about it, but to a coder, there’s a hundred anxieties associated with that:

  • What if the person doesn’t have a last name?
  • What if their last name is expressed as a mathematical equation?
  • What if their last name is longer than 255 characters?
  • What if their last name contains tab characters, multiple paragraphs, non-breaking spaces, emojis, parentheses, commas, single and double quotes?
  • What if their last name changes between the time when they type it in and the time when they submit the form?

To any normal human being, these questions are absurd. To a coder, they are common sense. What this means for you, as a designer, is that you must keep close to your coders, try as much as possible to anticipate the anxieties that will besiege them, and keep them from derailing the experience with utter lunacy.