the damage is done; what's done is done

done! that's that done!

to waste no time in doing something

(simile, informal) to be cornered, to be a dead duck

consider it done; it's as good as done

gentleness works better than violence; you'll get more by being kind than by resorting to violence

half-assed, sloppy, slipshod

(figuratively) where the shoe pinches

you can't judge a book by its cover (it is not possible nor advisable to judge things by external appearances alone)

money can't buy happiness