... is that you can create a liability on your own account, but you can only receive a credit on your account by the consent of someone else (who agrees to create a liability on their account).

The second difference is that you can fail to satisfy a liability that you have created, but you cannot fail to satisfy a credit that you have received.

Or, IOW, the debt/credit relationship is an asymmetric relationship.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.