March1, you say some people don't want to form friendships and are happier alone. I'm just like that, but, in addition (or maybe because) I really don't know how to be friends.
In a set situation, like work, study, community projects etc. I love the company and being friends seems easy. I'm happy to meet for a chat as well, often talking to other dog walkers or neighbours.
However, here at home, I'm reluctant to invite people - as it's my little sanctuary. I'm a terrible host, don't know what to do, say, cook or provide - just lost really.
Family and my one long-term friend just visit and I feel comfortable with them. I can be my real, awkward, unreliable self and that's enough.
Therefore, I tend to reject invitations to other's homes - as I don't want to return the favour. I'll suggest going out instead.
I don't tend to contact people, either, not wanting to impose or bother them. I wish there was a place I could go, just drop in when it suits me, when I'm feeling sociable.
My friend often pops into her local pub for lunch, on her own. I wish I had the confidence to do that.