Here are the top five ways to irritate your customers online:
1) Opening links in new windows: Often a gut reaction for businesses new to the web is to open all links into new windows. The rule of thumb is, if you are providing an internal link, linking to another page on your website, the link should open in the same window. If you're linking to another, outside site a new window can be used.
2) Music that plays automatically: Nothing is more nerve racking than researching information and landing on a site where music is blared at you. Worse is when no option is made available to turn the music off. If you offer sound, give the customer the option to turn the sound on and off.
3) Not properly testing your site in popular browsers. There are people that love Apple and have something against Microsoft. There are people who do all their work in FireFox. No matter what browser or platform you like the best when it comes to your website keep your customer's preferences in mind. You may love that new iPad but most of your customers are likely still using Microsoft.
4) Poor Navigation: Test your links. Make sure that customers can move back and forth through your site easily, and that once they find a piece of information they don't lose it again within your site.
5) Animations that interfere with information: Butterflies and growing flower animations are lovely but when they interfere with the reason your customer is really at your site the animations can become too much.
Minor irritations can cause a customer to forego your site for a competitor's site ruining your chances to stay in front of the competition. When it comes to the web, just like the physical world, keep it simple.