I can't express anything other than my personal opinion. So:
My housebun Hazel lived by himself for the 1st 18 months or so we had him. We're very close and spent alot of time together, though there was plenty of time that he was by himself as I work. But he loved us loads we loved him.. .
As other buns arrived with us - that were kept outside - Hazel could smell the doe on us I think and got quite frisky so we had him neutered. And after reading about the many bonded pairs and groups on here we decided to get the doe speyed and try them together.
Having bonded them I have to say that I would never ever want to keep a bunny singly (though occasionally I understand it is necessary) again.
Hazel and Tamlin adore each other. They play together round the house when we're home, chase and leapfrogging (i don't mean humping!) each other, and curl up together when they're sleepy, and Tamlin adores Hazel, seeing them cuddled up together, or them nose to nose as she grooms him just makes me melt.
I know that he is happier now he has her. No matter how much time I spent with him I can't relate with him the way Tam can.
All our other buns are in pairs other than one. Who is currently by himself (it really bothers me that he is, I'm "aware" of it every day) but we are currently sorting out another shd set up where I hopefully want to bond him back to his sister, mum, and other two brothers, who are all speyed and neutered.
So, sorry for the long post but I'm guessing that other people and rescues, like me, have seen bonded buns together, and after seeing that I think its difficult to sit easily with a bun living alone, unless like I say its absolutely necessary.
Sorry I'll stop now!