Not the TV series, but personal connections - what makes an acquaintance versus a friend, or a close friend versus a lifelong friend - and does being able to define and differentiate between them matter?

I have friends who I feel I’ve known for a long time, however some of them have childhood friends - relationships that span most of their life which sort of blows my mind. Others have close relationships with relatives that also span their life and while I have some long term friendships and some deep connections with the people in my life - I don’t have long term connections with anyone more than 40 years (that seems odd, but remember I’m in my 60’s). Sometimes reflecting on this fact makes me a bit sad and it makes me wonder why.