Do visitors love your website? Are you sure? Some brand websites look fancy, but when customers actually surf or shop the site they run away faster than a half-dressed girl in a scary movie. Why? Because there are certain website designs and features that drive people crazy.

We asked Brian Gatti, a senior marketing consultant at Inspire Business Concepts who handles customer experience design, to help us create a list of features that send your visitors screaming for the hills. Here they are:

1. Menus that are too clever

Customers are busy, and when it comes to checking out a website, they don’t dawdle. Research suggests 55 percent of visitors spend fewer than 15 seconds on your website. Considering you have a limited window of time, don’t waste it with menus that are too clever for customers to figure out.

For example, in an effort to stand out from competitors a pizza shop created menu tabs that were: who, what, where, when and why. The menu was located under why.

“Users are not looking for a clever experience,” Gatti says. “They want to find what they need quickly and easily. Fail at this and you will send them packing.”

2. Autoplay background music

It’s not the 1990’s anymore. That means body glitter, bib overalls and music that automatically plays when you arrive on a website are no longer in style.

“Background music is disconcerting and disruptive to the user experience,” Gatti says. “It can make your audience jump ship immediately. Frankly, it’s even worse if there’s no way to stop the music.”

3. Autoplay background videos

Since we’re on the topic of autoplay features, soundless background videos that autoplay are also causing concern. Here’s an example. It’s a fairly new concept, but the idea is to have some kind of movement in the background that brings a static website to life.

PayPal actually had an autoplay background video for some time, but it got mixed reviews. The site is now back to its original layout.

This feature is still in its experimental phase, and too many things can go wrong, Gatti says.

“Too many background videos on a single page or not being able to see enough of a single video can create a motion sickness kind of experience for the visitor. This will quickly kill any interest the visitor has in the site,” he says.

4. Sites that aren’t mobile-friendly

Last year mobile use surpassed desktop use, according to a ComScore report. So, if your website isn’t geared toward mobile users, you’ve got a problem.

Aren’t sure what your website looks like on mobile devices? Use a site like MobileTest.Me to preview your website on dozens of different mobile devices.

If you’re not pleased with the results, it’s time to make some changes to your site. Consider implementing a responsive website design. Sites that have this design look great on every device. From iPads to desktops, your site looks pleasing to visitors now matter device is used.

“If your website isn’t easily browsed on a mobile device, primarily a phone, you’ll send customers running,” Gatti says.

Websites have become a vital digital marketing tool for every business. More than $1.1 trillion in retail sales are “web influenced,” according to Forrester Research. In other words, customers search for products and services that they want before they buy. To make sure you get in on that action, follow the tips above to keep customers from bolting to a competitor’s site.