A server also might have a software problem just like your home computer. One program might decide it doesn't like another program and begin to cause problems for the whole system. These problems can easily slow a computer handling lots of Internet traffic. A third reason a site might be slow on the server side is an overabundance of images and tables and other graphical elements on a page, or graphics and images that aren't compressed properly for the Web. These images take a long time to transmit over the Web and bog down folks trying to see a site.
Network connections can experience problems just like servers can.
The Web is held together by a combination of very high-speed communications lines and some slower communications lines. Your Web viewing experience is only going to be as fast as the weakest link in the chain. So if the site you want to view is connected to the Web by a slow line, or if a guy digging a trench somewhere cuts through one of the big high-speed lines that crisscross the country, traffic is slowed or bottlenecked. The same principle applies to your connection to the Web. You can even experience problems because of software on your computer, though they're a little different from those of a bottleneck in the network.