Obligation. Is when initial passion deteriorates to fake concern and interest, and when the fickle mind or conscience prevents you from being who you are. It cheats people of who you truly are and gives them a false hope and impression that you are more noble, more caring than you are. It is the insulting status that you unconsciously place your friends at, and which the conscious friend will hurt at realization.

Don't be obliged to do anything. Not even to friends. It's not worth it cos it hurts the person more than it hurts you.

And sometimes, the hurt becomes a grudge and it never turns back from there.