18不解释
[18 bù jiĕ shì]
'Don't bother to explain at the age of 18.' For some teenagers, turning eighteen means growing up and maturing, thus hoping others treat them more seriously without over-protection or extra explanation on anything obviously reasonable. But in fact, some people think it unnecessary because misunderstanding will come naturally without further clarification when one grows up anyway. So they would prefer less verbosity and direct communication style at this stage of their lifetime.