has been closed as not a real question.
While the posting isn't particularly well formulated, the question itself can be meaningfully answered as various interpretations of quantum mechanics do give explanations.
Right now, the existing answers and comments lead to the impression that the question is either a philosophical one and thus off-topic, or that existing theories do not provide explanations, both of which I disagree with under the assumption that interpretations of QM are on-topic here.
Incidentally, I've also written an answer I wanted to post but no longer can ;)
This is my proposal for a re-write that's hopefully less confusing but still captures Outlier's intent and main points:
Are there theories that explain wave-particle duality?
I'm confused by the famous wave-particle duality mystery:
When a particle is left unobserved, it acts like a wave and can explore all classically available particle trajectories simultaneously. By looking at it, you force it to decide on a single trajectory, like going through the left or right slit, or like Schrödinger's cat that ends up being either dead or alive; the wave-like characteristics are lost.
Are there theories that actually explain this behaviour?
Should I go ahead and rewrite the question?