Cat related proverbs :) :)

• " A borrowed cat catches no mice " Japanese proverb

to describe someone behaving in an uncharacteristically quiet or well-behaved way, as a cat in unfamiliar territory.

• " the cat that swallowed the canary" English Idiom

when a person has an extremely self-satisfied expression especially while concealing something mischievous, prohibited, or private. In another meaning, A person whose appearance and behavior suggest guilt mixed with other qualities, such as satisfaction. For example: He talked freely ( as if he is an honest man) and carried the smile of the cat that swallowed the canary

Well, the original story of this Idiom: It tells about a hungry cat who looked at a small canary with a smile. then the cat said to the canary " you will be alright" when he swallowed it :)

• "Curiosity killed the cat" English Idiom

a warning not to be too nosy, seems to be a variant of the traditional "care killed the cat," a warning against overprotection. Another meaning, Getting yourself involved in things that aren't necessary can lead to bad situations.
The earliest printed reference to the origin of this proverb is attributed to the British playwright Ben Jonson in his 1598 play, Every Man in His Humour, which was performed first by William Shakespeare.The proverb remained the same until at least 1898.
"Care killed the Cat. It is said that "a cat has nine lives," yet care would wear them all out."
P.S in the arabic culture the Cat has seven lives only :)

• All cats are grey in the dark"  Englsih Idiom

Things are indistinguishable in the dark so appearances don't matter. Another meaning this Idiom can be used for, "All persons are undistinguished until they have made a name." 
Sometimes, persons tell themselves that Everything is the same color especially in devastated times, so they won't bother if they entered another trouble. There is an alternative phrase in Egypt said " They hit the one-eyed man on his lost eye, so he said it is lost". Sometimes, it is said when you are about to do something risky, you already have nothing, you say : What the hell?!  I have nothing to lose. A

• "While the cat's away the mouse will play" English and Egyptian Idiom

warns of behavior without supervision. Well thats a fact, when someone feel secured he does whatever he wants, as long as there is no chains.