When developing a web site, it is important to remember that the ultimate judge is the end user. If the site presents difficulties, people just won't use it. Here is a list of some of the most common website annoyances, most of which can be avoided quite easily.
Data Do's and Don'ts
Annoyance #1: No instructions regarding case sensitivity.
Encountered: User names, passwords, CAPTCHA verifications.
Solution: State clearly whether or not the input field is case-sensitive. It's not a big deal to have to hit the [Shift] key, but having to redo a field (or more) because of lack of clear instruction is frustrating.
Annoyance #2: No instructions regarding number formats.
Encountered: Dates, phone numbers, Social Security numbers.
Solution: Tell the user exactly what format to use and provide an example. Example:
Enter your birth date as DD-MM-YYYY, for example, 30-02-1985.
Determine the way your database formats these numbers and provide that information to site users. If only the numbers are stored, restrict field entry to numbers and note by the field that only numbers are to be used, no dashes, slashes or other special characters.
Annoyance #3: Error in one field causes entire form to reset.
Encountered: Profiles, feedback forms, registration forms.
Solution: If your system can't save valid input when errors are found, don't make forms with more than four or five fields per page. There are few things as aggravating as filling in 20 fields, mistyping an extra digit on a phone number, and having to start all over because the system rejected the one bad field along with all the other data. Ideally, use a system that retains entries that are valid and simply highlights fields that need correction.
Design Do's and Don'ts
Annoyance #4: Restricted contact.
Description: A user clicks a link that says "Contact us" and instead of being brought to a page with different options, an email form pops up (or tries to).
Solution: Make "Contact Us" a page that is linked to. Provide whatever specific methods and departments you can, such as connecting with the Director of Marketing on Facebook, calling or sending a fax, or emailing customer support about a common issue. Including an "email us" or "feedback" form on the Contact Us page is a good practice.
Annoyance #5: Links to nowhere.
Description: A link ends with "#" but no anchor name, so when the link is clicked the page simply reloads.
Solution: Links are the first, middle and last elements of a website that need to be checked and double-checked before users run into problems. In the early stages of a site, links may be intended to content that doesn't yet exist. Rather than putting in "placeholder" links to nowhere, wait until the content is there to be linked.
Annoyance #6: Limited compatibility.
Description: Website displays correctly and all scripts work in only one type of browser.
Solution: Use as many different systems and browsers as possible to view and use the site. Access it with web-capable phones as well. Many times, a site may seem to display correctly, but certain elements, such as a "Submit" button, may not function or in some case won't show up at all. If your site won't display properly in a particular browser, include such a warning in the site metadata so visitors are alerted.
Conclusion
Ultimately, your site visitors are the deciding factor when it comes to what works and what doesn't. Compromise must be reached between the goals of the owner, the desires of the visitors, and the capabilities of the systems in use. Keeping these annoyances in mind will make that compromise a little easier to reach.