Bad.

Watch a bad boss until you see what he does well. There's a lot to be learned.

Every bad boss has a skill that explains their rise to bossdom. 

One bad boss was superb at being able to concisely and accurately summarise a situation. He could sit silent for an hour or more at important meetings. Nodding and uh-huhing enough to appear engaged. At the end he would clear his throat, lean forward and list each discussion point, individual arguments for and against, action items, and those responsible for carrying them out. He was never on the list.

I would watch him at these meetings and think 'He sounds so intelligent. Maybe I've misjudged him. He's a good listener and has an impeccable memory. All the other executives seem to accept his authority, including the CEO.'

He reported what was, affirming by his simple narration the gravitas of each participant who had been absorbed in analysing the information. They assumed that because he was at the same meeting as them and they heard their words from his mouth minus the faltering cadence of raw thoughts forming sentences, that he was as smart as them.

He was essentially a tape recorder.  

Or the voice in a lift that reports before you exit: 'Level 7. Have a nice day,' as if it lifted you there on its shoulders.

The rest of the time he was bad. 

He was very senior in the organisation and was boss of dozens of people. I never knew him to make a decision. 

I once felt sorry for him. Being a boss is hard work. A different kind of effort is required to be a bad boss. The performance anxiety. The fatigue. The fear of being found out. Any sympathy vanished when I heard how much he was paid. Four times more than the nurse who cared for my sick child. Obscene.

We've all known bosses like that because organisations are suckers for thinking that being good at one thing means being good at lots of other things. 

It's like making the star juggler the manager of the circus. 

A bad boss is like a bad driver. They drive on - serenely indifferent to the other drivers breaking and veering and swerving and colliding in their aftermath. Their damage cascades down the organisation.

Bad bosses often teach us more than good ones, and definitely more than mediocre ones.  I know because I've learned so much from bad bosses.

Including that I've been a bad boss.