While trying to schedule an event online, I noticed something funny. There’s an optional feature to have the website remind you before the event, which I sometimes use for a 5 or 10 minute heads-up. But as I was scrolling through the choices, I noticed they switch arbitrarily between measures. After “9 hours,” “10 hours,” “11 hours,” it switches to “0.5 days,” which is just plain ugly.

Obviously, I know that 0.5 days equals 12 hours. Since 12 comes after 11, the menu is mathematically correct. But the inconsistent design is distracting to the user, requiring more mental cycles to browse through the list. Worse, if you’re looking for 12 hours, you might miss it entirely.

It’s no secret that variances in color, text size, and even writing style can be an effective way to highlight important points. But as this example shows, the same principle applies when you accidentally interrupt a clean design with something that doesn’t match up. It draws attention for the wrong reasons, and makes the product harder to use.