How many times have you been through the 'try this and try that' routine only to find that your connectivity or email problem spontaneously corrected itself.
More often than not, this is because it was never your problem in the first place—it was an issue with the Internet Service Provider.
Furthermore, such issues are often 'known' to the service provider though not necessarily to their support staff who would probably continue to work methodically through 'the script' even if their entire network had just been destroyed in a nuclear explosion.
In most cases, known issues are reported on a 'Service Status' page though this is often buried deep in the bowels of the company web site.
Happily, the people at Net Status have created a simple blog with links to the Service Status pages of most UK internet service providers.
A quick look at your ISP's service status could save you hours of argee-bargee.