How can people live in filthy surroundings....

There is this girl that I work with. She always wanted me to come and visit her at her place to hang out and watch movies are whatever. Which at first I was a bit skeptical and hardly knew her. I don't like visiting peoples houses if I rarely know them. I guess I just need to get over that. Well anyway, I decided to visit her place one day. So the moment that I stepped into her house, there was literally no were for me to sit down. Dirty dishes everywhere clothes scattered all over the floor and leftover food that was half eaten everywhere. I was like omg (not to her literally but to myself). How can anyone live like this. This is something I also never expected from her seeing her personality and all. I just wanted to either help her clean up or just go home and take a shower. I was afraid some kind of animal would come out and bite me or crawl up my leg. I just don't get how anyone can live like that.