The first way to work in harmony and have some fun with a no-decision boss is to make decisions in their place.
But this is dangerous, so you must take precautions and prepare in advance before you jump in and decide in place of your no-decision boss.
The first thing to realise is making decisions in place of the boss is against your organisation’s rules and is contrary to its structure. It’s against every procedure in the company. Your boss was appointed to make decisions in your department, not you. This is why it is dangerous. If you are discovered, at the very least you will be punished, at worst fired.
In addition it has never been taught anywhere, certainly not in any business school, so up until now subordinates have had to learn by trial and error on their own, making the process complicated. As an example here is what happened the first time I decided in place of my boss.
I knew an important purchase order would never be signed by my no-decision boss. I signed the order myself and sent it out to the supplier in a mail, with my boss on copy. I did not have the authority to sign the order but the supplier did not know this. The day before, I informed my boss that I would sign the order and send it out the next day. No reply from him. No comment at all. He changed the subject and talked about something else.
You might say this is delegation, but it is not. He was a true no-decision manager and they never delegate. Delegation is a decision. No-decision bosses never say they want their subordinates to make their decisions. It is up to the subordinate to step in and act on their own.
The order I signed was never audited. But if it had been, the auditors would have discovered it was not valid, and had not been signed in accordance with the company’s procedures. You can see that I protected myself, just a little, by copying my boss on the email. But as you can imagine, over time, it was not the only order I signed in his place.
So what are the precautions to take? First make sure that you really have a no-decision manager as a boss and not a manager that, for instance, is slow to make decisions. Take the time to understand no-decision managers. They actively seek people to make decisions in their place BUT they never protect anyone if the decision turns out to be a wrong one.
And what are the decisions you have to make? The most important is what level of decision-making are you willing to risk? Another is do you inform the no-decision boss that you have made a decision after the fact, or as I did, inform them before. You can also you never tell them and just decide. It depends on the level of decision-making and the risk tou are willing to make.