Latency is delay on a computer network. It causes a poor user experience. This is very evident in real-time communications like Internet video streaming (e.g. Netflix), Internet video conferencing (e.g. Skype), and Internet video gaming. Please see Network Jitter for more details.
People using the Internet are frustrated by slow Internet speeds caused by latency. This is evident when web sites are slow to connect, and web pages are slow to download and render. This is why most people think of a latency as "bad". Please see Network Latency for more details.
Please see Internet Protocol Suite for more details.