Idleness is the mother of all vices.

Evil thoughts often come from idleness.

I don't think necessity is the mother of invention. Invention, in my opinion, arises directly from idleness, possibly also from laziness - to save oneself trouble.

Idleness is the beginning of all vice, the crown of all virtues.

If you don't want anyone to know it, don't do it.

The willing contemplation of vice is vice.