Welcome back. With user stories just like any story, there's always a chance that things might not go exactly how you want them. The hero detective doesn't always crack the case, and your user doesn't always reach their goal. Luckily for your user, you can change their experience as a UX designer. When building a new or improved product, the designer's goal is to keep all users on the happy path. The happy path describes a user story with a happy ending. For this user, everything goes as they expect and they reach their goal without issue. Unfortunately, for other users, things don't go quite as smoothly. For example, let's say Iyler, a land owner, wants to buy birthday flowers for her friend Priya in California. She visits the website of a California based flower shop and gets to work designing a bouquet of Priya's favorite flowers and writing a meaningful message. Everything is going well. Iyler's on the happy path. But when Iyler asked to enter her address, there's a field that asks for her home state. Iyler doesn't have a home state, she lives in London, England. She tries to skip that field, assuming the site will let her, but the state field is required to proceed. She reaches a dead end on the happy path. After all that work, has to close the website and find another way to get flowers for her friend. In the design world Iyler and others like her are called edge case users. An edge case is a rare situation or unexpected problem that interrupts a standard user experience. Good UX anticipates edge cases and reroute users back to the happy path when things don't go as planned. In edge cases, the obstacle is often beyond the users control to fix. Think back to Iyler who only wants to wish her friend in America a happy birthday. There is no way for her to skip the state field, so there is no way for Iyler to successfully buy Priya's flowers on the shop's website. Unfortunately, Iyler's user experience is unrepairable on her end. Let's check out some UX design pro tips for spotting and resolving potential edge cases before the product launches, so other users don't end up in Iyler situation. Pro tip 1, create personas and user stories. If UX designers make sure their personas and user stories account for a wide variety of users and problems, they can keep even the most vulnerable users on the happy path. Pro tip 2, thoroughly review the project before launch. In the rush to launch a product, UX designers might focus only on the happy path. Giving the project of final good review from the user's perspective, helps designers identify edge cases. Pro tip 3, use wireframes. You'll learn how to create wireframes later. Wireframes help visualize the project, which makes it easier to identify potential user pain points and fix them before launch for folks who are not visually impaired. We all have that friend who always has whatever you need when you need it. For example, if you're at an amusement park having lunch and dropped your fork on the floor, this friend's got an extra fork ready to go. Need an extra pair of nylon footies to try on some fancy flats? They've got you covered. As a UX designer, you want to be that friend to all users. You want to be able to anticipate what needs they might have, whether they're on the happy path or not. Okay, so far we've gotten to know our users and their stories. Up next, we'll go on a journey. The user journey.