I think daintytoes, you have explained it really well.
This is how I imagine it working.:
Scenario , Getting an early night.
Adult to adult:
You: you look tired love, why don't you get an early night?
Them: I'm just watching this programme and then I' ll come to bed.
You: ok, how long is it?
Them: just another hour
You : oh that will make it midnight
Them: I know but it's the last one in the series
You: if it were me I'd leave it to watch tomorrow, night night.
( fine if it's your DH, but you've not got them to bed, but you have avoided confrontation this one I do too oftentimes avoid a row)
Parent to child
You: you look tired love, you need an early night tonight
Them: I'm just watching this programme, them Ill come to bed
You: no, save it till tomorrow, you'll be tired all day. I'll make you a hot chocolate and that's my final word
Switches TV off
( fingers crossed this works, may take a much longer convo!)
Child to child
You: you look really tired, why don't you go to bed instead of getting yourself really knackered and bad tempered tomorrow like you usually are. It's a stupid programme anyway.
Them : shut up, it's really good, better than your stupid programmes.I'm watching this last programme then I'll come to bed, idiot.
You don't you speak to me like that you cheeky little brat, filling your head with rubbish. Get to bed, now!
Them: no eff off
Etc!!!
( this is how you feel, just spilling out and it makes things worse!)
Child to parent
You: you look knackered already, god help us all tomorrow if you don't get an early night, I don't think I can put up with it anymore. It's a stupid programme anyway.
Them: you have no idea what this programme is even about, do you.? And, if you think I look knackered, have you taken a look in the mirror? You're the one that needs to go to bed.
You: I'm just going to scream if you don't do as you are told FOR ONCE
Them. Here we go again. I'm not listening to you anyway.
Etc
Haha that was a loooong post, sorry.