Why are little kids so annoying and crazy?

i'm 14, and all my little cousins are over at out house right now. it's like 5 of them and the oldest one is 8, and the rest are like 3-5. since they got here, all they've been doing is screaming and running around the house, throwing things down the stairs, etc. and they keep coming into my room and jumping on my bed and pull on my laptop, and it makes me wanna sock them in the face. and there parents are all downstairs! it makes me wonder if they do this at their own homes, and just act like complete hooligans. i know that my brothers and i didn't act like this when we were their age, because our parents didn't allow us to make complete fools of ourselves. if they saw that we were out of line, they disciplined us in ways that would not wanna make us ever even think about acting like that again. these kids are soooo annoying! it seems like they have no parental guidance which causes them to act a fool. and please don't say, "oh there just kids, let them have some fun!", because there are other ways to have fun which doesn't involve slamming every door in the house or screaming and throwing tantrums