What does "Shit happens" mean in Forrest Gump? What’s the deeper meaning? Why can't I see what's going on with him?

This sentence means "Occasionally, unsatisfactory things will happen in life, and there is nothing worth making a fuss about."

"Shit happens" is a common mantra in American colloquial speech. The original meaning of shit here is "excrement; feces", which is extended to "bad things". happens means "happen". The meaning of the entire sentence is: bad things will inevitably happen.

Extended information:

Shit happens is a common slang term that uses a simple existential observation that life is full of unpredictable events. This phrase acknowledges that bad things happen when There is no specific cause in people, and its origin or earliest use is uncertain.

The closer translations of "shit happens" in Chinese include: things are unpredictable, things are impermanent, the sky is unpredictable, bad things are inevitable in life, etc. Phrases with similar meanings, such as "stuff happens" or "it happens."