The true definition of...

a best friend and a friend.

From Gan Jay Han's dictionary of life...

Friend - Someone who might misuse you as their slave when they need you but when you need them, they are no where to be found. Even if you found them, reasons will be given to be excused for not helping you. Some which are not even reasonable to be excused. They are also the one that doesn't appreciate you when you help them. That's just friend.

As a summary,
When they need you,
You're there for them,
But when you need them,
They are nowhere to be found.

Best friend - Someone who cares for you, who suffer with you, who is happy when you are happy, who is sad when you are sad, who will cheer you up whenever you're down, who help you through various obstacles that you can not go through. Someone who also remembers the deed you did for them and waiting for their chance to pay back. That's a best friend.

As a summary,
When they need you,
They'll appreciate you the most,
And whenever you need them,
they are always there for you.

I've just change my perspective of viewing a person.
A few people had been dropped off from my list of these two categories.
I'm very sorry, but this is what you get for treating me this way.
And I'll just treat you guys back the same.
It's KARMA, what goes around, comes around. Thanks