Very in agreement re disingenuous "niceness", only want to add that in adult-adult interactions it's just as frustrating.
I do think there are a lot of parallels in the boss-employee or mentor-mentee adult relationships to parenting. In the ideal senior role model/boss/manager/mentor we want somebody who is flexible and understanding, but ultimately gives clear directions, is a strong role model and knows when to take charge. They are easy going enough to let small things slide, but take important things seriously. They give us freedom over decisions we are able to make autonomously, but guide us firmly where appropriate, so we can learn from their experience and knowledge. They seem to like and respect us, and will warmly praise good work, but will also challenge us and be honest, frank and fair about areas we can work on to improve.
Eg: Boss asks
"Do you think you could please get that report done when you're able?"
And on Monday they ask why it isn't done and appear frustrated, angry or critical.
Vs
"I want you on the report. It needs to be in by Monday" (obviously with a willingness to listen if there are obstacles to you doing this). On Monday as the report is done on time, you are thanked and/or praised.
We all know which scenario is better and the "please" matters not. Adults and children hate fake-nice indirectness and having to second guess the consequences. We all want those in authority over us to set clear expectations without being despots.