Sorry is a very simple word that can save a relationship.

This "seemingly simple" five letter word has made alot of promising relationships to crumble.
You also nailed it with this:

"I am sorry" would not cost you a thing. It really would not. It also will not make you a less human than you are.

Thank you for this powerful piece @ogoowinner.
Happy birthday to your Elder sister. I wish her long life in good health.
Happy sunday.