Best friends often make good partners in relationships, because they really care about how you feel, however if the relationship doesn't work out, that would be some messy business.
Best friends don't talk about eachother behind their back, say their best friends one minute, and then decide the next day they don't want to talk to you. They say they love you and ACTUALLY MEAN IT.
Best Friendship consists of love, loyalty, kindness, selflessness, thoughtfullness, and making sacrifices for the other.
Your not best friends with someone for their car, or their money, or their popularity, but because you like them for who they truly are, deep down.
Some best friends can make mistakes, hurt you, and mess up alot, but you have to be forgiving so you can let them try to make up for it. A letgo best friendship is the saddest thing ever. A bestfriend is loyal, true, and will never forget you.
Lyrics that explain it well, and correctly:
If your heart is always breaking, cause the worlds just not fair, when your at your worst, your friends the first one there. Giving you something to lean on, and thats what it means to be a friend.
EXAMPLE OF WHAT ITS NOT:
Clara: OMG I LOVE YOU YOUR MY BEST FRIEND.
Jill: Love you too, best friend!
(Jill walks away)
Clara: OMG I HATE HER SO MUCH. DID YOU SEE WHAT SHE WAS WEARING?