The characteristics of speech are influenced by environment, so considering that we learn languages in our infancy, it's not surprising that people speak like their peers. In the UK you can find a large variety of accents. If you're accent-savvy, you can usually pinpoint someone's origin to the nearest major city.
Usually, the difference between two accents of the same language comes down to the pronunciation of vowel sounds. Think of the classic song "Let's Call the Whole Thing Off"... "you say tomato (/təˈmeɪtoʊ/ or tə-MAY-toh), I say tomato (/təˈmɑːtoʊ/ or tə-MAH-toh)".
|If you speak with any kind of an accent this is irrelevant.|
The main problem I've encountered with accents is their ability to remind the listener of certain stereotypes, which is creatively known as accent stereotyping. It's difficult to hear a Southern American accent without thinking that someone is a redneck, especially for Brits who often only hear the accent spoken by cowboys and incestuous gun-wielding lunatics. This, obviously, is not true for everyone who speaks like this.
|Apparently "Scotland" is an accent now.|
Unfortunately, not everyone will be open-minded when they hear certain accents and you may be victim of accent discrimination. However, it is fair to say that if you do have an accent, you should consider softening it for foreign speakers and even those who may not be familiar with it. After they are familiar with it, you can get drunk, speak naturally and blow their minds with your exotic use of their mother tongue.