The saying one bad apple can spoil the bunch is so true. If you have a bad apple on your team, you need to immediately get rid of him. I know it is very hard right now to find staff, but what is truly worse than being shorthanded is staff that's full of negativity that doesn't produce. If you treat your staff right, they will treat you right.
But sometimes you might find a staff member that is negative, holds grudges and goes out of her way to make life difficult for you. Negativity spreads like a wildfire. Once you find out who the lead bad apple is, you need to say goodbye, sayonara, adios, goodbye, and you need to do it immediately. No hesitating. Fire quickly, hire slowly, follow this rule and you will get yourself a great team. Do that immediately, find some great A-players, and stay focused, my friends.