You turn around and suddenly notice that they are growing up

Standing at the parking meter

She: Um, dad, you put that last quarter in the dollar slot.
Me: It's been a long day and I'm getting a bit tired. I'm not thinking straight anymore.

I fumble for more change

She: Here, take one of mine

She hands me a quarter.
I turn to look at her and notice that she is taller than my shoulder.

Me: When did you grow so tall?
She (with a small smile): I'm standing on my tippy toes.

I smile at her, relieved.

Me: Stop that. You're making me feel old.

You have children. You work hard to support them and give them all the material things. It takes most of your time. When you are home, they are usually asleep. Then one day while you are out with them somewhere, you turn around and suddenly notice that they are growing up. Scary.