It's been known to happen. Usually the result of a particularly stressfull week or exhaustion. Nothing with any kind of pattern though. If it's happening more often than you feel comfortable with, or you can't pin down any possible reasons behind it...look into it.

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Though I am different from you,
We were born involved in one another.

For it was not into my ear you whispered, but into my heart. It was not my lips you kissed, but my soul.

Complete surrender should not just come at moments in which one faces overwhelming odds, but in the calm when it seems one is personally in complete control of one's life.