I've always found that one of the hardest things about living with other people is having different metrics of tidiness. I'm not a complete clean freak, but I like to maintain certain standards. I also know that it's important for my wellbeing to try and stick to them. There are always going to be times when I'm busy or stressed, and these things aren't quite as achievable — still, I (mostly) try to keep my mess out of the way of others.
I know that there are plenty out there who feel similarly to me, but we don't necessarily hold the prevailing opinion. One look at the average houseshare will tell you that there is a very wide spectrum of what is considered to be an acceptable way of living.
By and large, those at the more disgusting end are usually more difficult to live with. This was demonstrated recently by one Twitter user who shared the conditions that their former roommate had made them live in. Including an unholy amount of food in the sink and unwelcome leftovers in the dryer, many were horrified at what they had put up with. Not everyone was quite so sympathetic, but it was hard not be with the photographic proof.