The Andalusian accent is a very distinct accent in Spain. People in Andalusia talk really fast and usually don't say the "s" at the end of words. For example "buenos dias" is said "bueno dia" without the "s" at the end. This makes it really hard to understand for learners of Spanish. However southern Spain is also a popular destination for people (especially Europeans) to come and learn Spanish. After a while of being there, you get used to the accent and even start dropping the "s" yourself!
Wikipedia Article on Andalusian Spanish