That living without flatmates improves quality of life a million fold. No-one to dominate the living room by continuously watching reality TV, use up the hot water, cook smelly food, or randomly fly into an apoplectic rage about the kitchen cupboards being dusty. No-one that you have to ask whenever your friend/sister/parent comes to stay, or if you want to have people over for dinner.
True, I've had some great flatmates over the years, and some good flats. The last year in London in particular though we had some flatmates that left a lot to be desired, and were totally ready for our own space. Now it's me hogging the TV, and I love it.