Sometimes, it's not about doing too much, but about doing things at the right time. A common example that's often mentioned in literature is sending emails within a web application. In this case, increased response times for HTTP requests may not necessarily translate to your code implementation. The response time may be instead dominated by some third-party service, such as a remote email server. So, can you ever successfully optimize your application if it spends most of its time waiting on other services to reply?
The answer is both yes and no. If you don't have any control over a service that is the main contributor to your processing time—and there is no faster solution you can use—you cannot ...
