Just say I am busy!

When I feel disappointed in someone, I want to repay him.
But I talk to myself, should I? Is it really make me feel better?
It's hurt when someone doesn't pay attention to you while you are giving a full expression to him.
No, I am not talking about a relationship, it is about treating a person well.
How do you feel when someone doesn't reply to your message during your waiting time, every day, every week? in a month or a year? it is insane. Why do you do that, just say I am busy sorry I cannot reply to your text message. DONE! I will not be waiting anymore.