Any time you struggle with a bad habit, addiction, or compulsion you don't have under control.

That's not uncommon in trades - plumbing, construction, auto mechanics and the like.

There are tricks and techniques that one can learn over time to make things easier or more efficient, but they're often complex enough or require enough skill and experience that if you don't know what you're doing, you're just going to unnecessarily screw things up trying. So new people are taught the standard, safe, dependable way of doing things, even if that's not the way the old hands do it.

Edit to add: in a moral context rather than a practical one, I don't think it ever is appropriate. IMO, the first requirement for any moral stance is that one abide by it oneself, and unless and until one has managed to accomplish that most basic of tasks, one has no standing by which to even meaningfully comment on other people's behavior.

• crocodile wrestler "Stand back, I'm a professional, do not attempt to wrestle the crocs yourself"

• pilot "Please remain seated, no you cannot have a go"

• holding someone at gunpoint "Empty your pockets, this is a stickup. Oh shit, you've got a gun too?"

Any time there's a skill discrepancy that enables one to do things in a more dangerous but more convenient or effective fashion and where someone else is yet to acquire that level of skill.

Probably an addicted smoker parent with throat cancer to their child.

It's technically appropriate anywhere where the teacher who knows how to do something has lost the capability to do it and instead is giving the knowledge to someone who still has the capability.

I tell co-workers that in a different way! There are certain tasks that I do in a database, that if I do it I do it through T-SQL, but I tell newer techs to do it through the UI because it's safer. Or I tell them to use simplified scripts that take longer, but require less knowledge from the user.

Or like we have this script that lists like 40 potential issues. New folks are told to just fix all of them, but for folks who are very familiar (or wrote the scripts) I'm aware there are certain ones I can skip if other problems are present, because in certain situations they can fix each other.

So "I know what I'm doing, don't do it this way until you know what you're doing" I think is appropriate in a lot of things.

When driving a car. Don't want the passenger grabbing the wheel!

Anything that someone is warning of their addiction to others.

When you can deal with the aftermath but they can’t.

When a former sportsman, now a cripple teaches a youngster "some moves".

The moment you done effed up while everyone's watching.

For me there isn’t one; I tend not to ask people to do things that I wouldn’t do and as a team leader I’m aware that those around me are learning through observing me - I don’t want them to learn bad habits so actually their presence keeps me in check.

Me, telling people that brushing their teeth is a good idea

Downs another naproxen