Second, some of them are easy riders. They are very lazy and selfish, they just want to enjoy the life, and so they just stay home to be a Neet.
Third, some of them have difficulties to obtain employment, like low degree. They often go back to school to continue study. That’s why there are so many people to be graduate student or even higher.)
I don't think that Kippers can be regarded as parasites, because this word is rather derogatory. Nevertheless, I can understand that some parents call them parasites as they quite often take advantage of the situation. It is quite difficult to understand why they do not take their share of the domestic chores. They are not children any longer and could understand that they may represent a "burden" for their parents who are not as young as they were before and that their help would be welcome. This is probably the reason why parents quite often resent their adult children living at home. However, we must understand that since the economic situation has become difficult, it is very hard for them to provide for themselves and to stand on their own two feet. They have no choice but to stay at their parents' home. To conclude, I would say that if adult children didn't take advantage of the situation so much they wouldn't be regarded as parasites. To avoid it, they should help at home and should also take part in the management of the household instead of behaving like parasites.