I was thinking about the saying "you have to grow old but you don't have to grow up." But I finally figured out what I don't like about that. Growing up is important. It's a good thing. It's why you can pay your bills and make wise decisions and learn from your mistakes to make better choices in the future. I want to grow up.
When people say this, what they really mean is that they don't have to grow out of things.
Growing old: spending more time alive. This is not optional. (Unless you die.)
Growing up: becoming mature and responsible and obtaining knowledge (and applying that knowledge to appropriate situations).
Growing out of something: no longer being interested in something deemed to be suitable for a younger age group than the one you are in.
So... you have to grow old, you should grow up, but you don't have to outgrow.
This is probably the sort of thing that belongs in /r/showerthoughts but I was pretty proud of it.