I agree with G, a good boss is a good communicator and involves support staff in things.
I would also add that a good boss respects all their staff; delegates responsibility, where appropriate; does not "micro-manage" staff; acknowledges achievement; motivates colleagues; manages time effectively and plans accordingly, and has good leadership skills.
I've had one boss whom I would rather forget (but her tenure of her post only lasted six months) and other bosses who, like the curate's egg, were "good in parts". Present bossie is great to work with. She works hard, is pro-active, very fair, treats me like the grown-up wot I am, and makes me cups of tea. I trained her well in the past year

.
Raindance