I have had many "best friends" over the course of my life. Friends from childhood, friends from school, friends from the neighborhood, etc. - various people have held the treasured title of "BFF". We would spend every waking moment together and then, gradually, for whatever reason, the friendships would begin to dissolve and we'd eventually lose touch. There was rarely bad blood - just the happenings of life. Then, after I left school and entered the working world, friendships were even harder to come by as we were all busy and didn't have much free time. I'd develop close friendships with the people I worked with, but we generally didn't hang out outside of work (with a few exceptions). Now, after getting married and having kids, most of my free time is spent with my family, and friend time gets pushed to the wayside sometimes.
But I've come to realize lately that this need to put a label on friendship is silly to me. There are people I'm friendly with in certain situations - work, gym, my kids' friends' parents, etc. There are people you've known your whole life and know everything about you and love you no matter what. There are friends for certain seasons of life. There are friends that you adore, but may not see every day, but when you do get together, you pick up where you left off, as if no time had passed. Online friends who you've never met in person. There are friends who just "get" you, and conversation isn't always needed - just silly memes and articles that remind you of each other.
All of that to say - I don't have a "best" friend, that one singular person who is somehow worthy of this special title at the exclusion of everyone else. But I have friends and I cherish them all - in every form and fashion that the friendship takes. I don't think any one of them is better than the others. They are all unique in their own ways and they each bring something special into my life. And I hope they feel the same way about me. :)
Making and maintaining friendships as an adult is hard. There's never enough time in a day, week, month for me. And time flies by so fast that when I blink, I realize it's been 6 months since I've seen so-and-so. And it makes me sad, but I know that it's just the season of life that I'm in right now. And I can call up any of my friends to make plans and they won't judge. They're just as busy as I am.