Do people really enjoy being on their own? Or is that a defence?

I do mean this from a position of wanting to understand rather than a belittling way. I've never had any issues talking to new people - I'm interested in new people (hopefully not too nosey!) and enjoy having a chat. I respect that's not for everyone and I do try and be aware of signals if someone wants me to move on. But if I'm honest I struggle to understand that some people do truly prefer being on their own. Of course, I do enjoy a walk on my own sometimes and reading a book quietly some afternoons but on the whole I really get such a buzz and companionship out of talking to others. Do some people really enjoy being on their own?