Ex-couples are often known for parting ways and not even sticking around for a friendship.
If you previously loved your best friend regardless of circumstances, chances are you'll remain great friends should your romantic relationship dissolve.
Not only does your buddy know what you hate about yourself, but you also know his/her deepest secrets as well.
Somehow your best friend has come to accept you for who you are, so perhaps this is a sign of better things to come.
This one may seem obvious, but best friends often take it for granted.