I've been thinking a lot about this, everyone's posts are really interesting.
I think that firstly some people use "best friend" to mean a friend they 'rank' as the absolute best. When others like myself say best friend, I'm not really thinking about it comparatively, I just mean they're very, very close to me. I've never thought of it as like a category or a status that only one person could have.
When I describe my mum as my best friend, I can't actually put into words why she is. She just is! My dad, on the other hand, is not my best friend. I love him the same as I love my mum, and I know that they both love me the same as eachother, but I just have a different relationship with my mum.
She's still my mum, and she still acts like my mum. The "best friend" part is almost secondary to the mother-daughter relationship. And I don't think that means our relationship is in any way superior to people who aren't best friends with their parent, it's just different. And we've not always been best friends, either. But she's always been my mum.
In the same way, my husband is also my best friend. But the way in which he's my best friend is different to the way my mum and my other friends are my best friend. And him being my best friend is secondary to him being my husband.
And when I think of the handful of girlfriends I'd describe as best friends, all of those friendships are slightly different too, with different things we can talk to each other about and different ways we spend time together and interact.
Does that make even a tiny bit of sense? I'm not very good at explaining things.
I also just wanted to make a point about the poster who have a niece they're concerned about as their only best friend is their mum. I understand why that's worrying, but I just wondered if maybe the following could be applicable...
If you had a daughter who was having a really hard time making friends despite all your encouragement, would you not fill that role for her until she finds her social circle? If your daughter had no friends, you would probably want to make sure she was still getting out the house and doing fun things, so you'd end up being the person she does that with. Maybe the mum is trying really hard to encourage the daughter to have friends behind the scenes and boost her confidence, but all anyone else sees is her spending lots of time with the daughter.
I'm sure you know the people in question best so you're probably right about their intentions. But I just thought I'd moot the possibility 