Note: This page was written to specifically to explain why an Apple iPhone takes "ages" to check the settings of an email account. In that particular case, the iOS software was trying to do things the "Apple Way", even after it had been told not to.
Sometimes "Software" does not always work quite the way that you think it should. Or, it seems when you approach a task in a logical manner, things start NOT to make sense quickly...
Most people put this down to bugs in the software. Software designers however sometimes feel that the thing you are trying to achieve is not correct, and therefore the fact that the software will not let you do those things is actually a useful feature.
Some software designers will now claim "feature" when you say "bug". So who is right?
Generally, if it does not work, and you are using the software for the exact purpose for which it was designed, it can be considered a bug. If you are using software in a way which it was not designed to be used, then the "feature claim" is probably right.
Often the real problem is that the software does not give a good response to a request it cannot deal with. Take your web-browser as an example. You may request to navigate to a page, and the browser-software refuses to show you that page. As it just does not show, you think there is a bug. The software-designer however had put in a "feature", which would not allow the display of pages from sources known for infectious code.