Can I raise a lighthearted downside?
It's the same as the positive that many people have mentioned: there's no one else to make mess in Your space.
This means, when you get impromptu visitors, they know its you who's the scruffy git as there's nobody else to pin the blame on!
On the positive side, if you want to be a grouchy fucker, there's nobody to a) ask what's wrong and what they can do to help constantly, b) think it's their fault, c) silently judge you when you're grouchy for the simple reason that someone nicked your favourite red plastic 10p pen off your desk, or d) sulk back at you all negative reactions were twatfaced ex, not DH by the way
If you don't fancy going somewhere and say you have plans elsewhere that night, there's nobody to accidentally drop you in it and say later on, all confused, 'but we didn't go to the cinema this week??' When you have that excuse for not going flower arranging with someone you don't really like. Nobody knows where you are, so you can use any excuse you like.
Getting hooked on TV shows that are only on at 1am
Having a kip when you get in from work and nobody knowing you're a lazy fucker. Although this was probably linked to the point above it.
When you're skint and/or don't really fancy going out, there's nobody else to consider when you say to a friend to just bring a bottle of wine round and watch shit TV.