You can only be young once. But you can always be immature.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of the mature man is that he wants to live humbly for one.
growing-up Die wilhelm-stekel
Humanity has advanced, when it has advanced, not because it has been sober, responsible, and cautious, but because it has been playful, rebellious, and immature.
Because Playful Been
The mark of the immature man is that he wants to die nobly for a cause, while the mark of the mature man is that is wants to live humbly for one.
catcher-in-the-rye Maturity immaturity
You are only young once, but you can stay immature indefinitely.
Immature poets imitate; mature poets steal.
I happen to be immature, undisciplined, and self-centered, pretty much a little boy in a man's body, although I'd appreciate it if you didn't quote me on that.
Basically my wife was immature. I'd be at home in my bath and she'd come in and sink my boats.
You're only young once, but you can be immature forever
fiction young-adult life
It is natural for the immature to harm others. Getting angry with them is like resenting a fire for burning.
The immature think that knowledge and action are different, but the wise see them as the same.
Nothing whets the intelligence more than a passionate suspicion, nothing develops all the faculties of an immature mind more than a trail running away into the dark.
curiousity mystery puzzle