Site Speed
If your website takes too long to load, there’s a very good chance that a potential visitor will give up and leave. They can just close the window and click another link from the search results. This is especially true for mobile Internet users, who tend to be very impatient. If a mobile user is looking for a local restaurant right now, even if your website is ranked at the top of the search results they may click on another link if your site takes too long to load. And that means a visitor that would have wanted to go to your restaurant for dinner tonight has now gone to your competitor.