Inspired by Horseradish (Bitter Truths You Can't Avoid) by Lemony Snicket:
I thought it hurt, because he left quietly. He packed his bags in secret. He tiptoed down the stairs, crept through the kitchen, and muffled the door on his way out. Or maybe he snuck through the window with his shoes in one hand, shimmied down the drainpipe, and rolled onto the grass. I don't know how he did it, but when I woke up in the morning, he was gone. And I didn't need a note to know that I would never see him again.
But you took your time to leave, and you didn't try to hide it. I watched you put things (both ours and yours) away, piece by piece. You stomped your feet, slammed the cupboard doors, and shook the walls as you dragged your suitcase through the house. You watched me chase after you and then stop myself, as if you needed my permission to go. The engine roared as you drove away, and I had to double-check through the blinds to make sure you were really gone.
And then I realized, it doesn't matter how they leave. It doesn't matter if they sneak out in the middle of the night or if they wait for you to lock the door behind them. It doesn't matter if you're left wondering how long they had spent planning their route out, or if you can still remember exactly how the backs of their heads looked like as they were walking away. It doesn't matter how they do it, it just hurts when people leave. Period.
Sometimes you need to recognize that you are not sad because of how a person left, what they did, what they said, who they left for, why they left, what they left behind, and what they took with them, because you know that at the time, it was probably the best they could do. You are sad simply because they are not there when you want them to be. And even that in itself, sometimes, cannot be helped.